Number Of Multiple Births Research Articles

Eclampsia, in vitro fertilization and the risk of preterm birth: a retrospective cohort study based on 2,880,759 samples.

Eclampsia and in vitro fertilization (IVF) are independent risk factors for preterm birth. Understanding the combined effects of multiple risk factors for preterm birth is critical to making accurate and personalized risk predictions. This study aimed to explore the interaction between eclampsia and IVF on the risk of preterm birth. A total of 2,880,759 eligible participants from Birth Data Files in the National Vital Statistics System (NVSS) database 2019 were enrolled in this retrospective cohort study. Some characteristics were collected, such as maternal age, prepregnancy body mass index (BMI), history of preterm birth, paternal age, race, newborn sex. Preterm birth was defined as <37 weeks gestation. Univariate and multivariate logistic regression models were utilized to assess the associations between eclampsia, IVF and preterm birth. The odds ratio (OR) and 95% confidence interval (CI) were calculated in this study. Relative excess risk due to interaction (RERI), attributable proportion (AP) and synergy index (S) were adopted to evaluate the interaction between eclampsia and IVF on the risk of preterm birth. The age of mothers and fathers, the number of multiple births, the proportion of mothers with a history of preterm birth, pregnancy infections, eclampsia and IVF among the preterm birth group were all higher than those among the non-preterm birth group. The incidence of preterm birth in eclampsia and IVF population was approximately 37.31% and 22.96%, separately. After adjusting some covariates, subjects with both eclampsia and IVF had a higher risk of preterm birth (OR =9.197, 95% CI: 6.795-12.448, P<0.001). Furthermore, the results (RERI =3.426, 95% CI: 0.639-6.213, AP=0.374, 95% CI: 0.182-0.565, S =1.723, 95% CI: 1.222-2.428) suggested that the interaction between eclampsia and IVF on preterm birth was statistically significant, indicating a synergistic interaction. Eclampsia and IVF might interact in a synergistic manner to increase the risk of preterm birth. Awareness of the risk profile associated with preterm birth is crucial for pregnant woman with IVF to implement dietary and lifestyle modifications.

133 NONINVASIVE ANALYSIS OF EMBRYO METABOLITES USING NUCLEAR MAGNETIC RESONANCE

Wide-spread use of IVF has significantly increased the number of multiple births (Janvier et al. 2011 J. Pediatr. 159, 409–413). A potential solution to this problem is to develop improved methods for embryo selection to permit single-embryo transfer. Identification of a noninvasive technique to assess embryo implantation potential in assisted reproduction would greatly increase success rates and lead to more efficient single-embryo transfer. The aim of this study was to assess whether there are metabolic differences among embryos produced by IVF and embryos obtained by parthenogenetic activation. Matured bovine cumulus-oocyte complexes were fertilized in vitro according to our standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Presumptive zygotes were placed in individual drops of 50 μL of SOF. Zygotes were incubated in a humidified mixture of 5% CO2, 6% O2, and 88% N2 in air at 39°C. For the parthenogenetic group, the oocytes were activated by 5 μM ionomycin in M199 + 10% FCS for 5 min, and incubation in 2 mM 6-DMAP in M199 + 10% FCS for 4 h. After 48 h, the zygotes were placed into WOW culture and the drops collected in tubes. The embryos were scored for quality on the basis of morphological criteria. Samples of media (40 μL) were added to 660 μL of a stock solution prepared by dissolving 5.0 mg of sodium 3-(trimethylsilyl)-2,2′,3,3′-tetradeuteropropionate in 50 mL of deuterium oxide. The sodium 3-(trimethylsilyl)-2,2′,3,3′-tetradeuteropropionate acted both as a chemical shift reference and as an internal standard for the purposes of quantitation. Samples were analysed on a Varian VNS-750 NB (750 MHz) spectrometer (Agilent Technologies, Santa Clara, CA, USA). Data were statistically analysed with ANOVA using the Generalized Linear Model (GLM) procedure (SAS, version 9, 1999, SAS Institute Inc., Cary, NC, USA), where the independent variable was the sample (IVF or parthenogenetic embryos and control media without embryos). Tukey's post-hoc test was used to perform multiple comparisons. The P-level was set at 0.05. All data were expressed as quadratic means with standard error of the means. The results, reported in Table 1, show that there were no statistical differences between embryo metabolites with IVF or parthenogenetic activation when we evaluated lactate, formate, myo-inositol, and pyruvate. However, we can see that there are differences when we focused on acetate and citrate. Parthenogenetic embryos produced more citrate than IVF embryos. It is well known that the Krebs cycle produces one molecule of acetate for each molecule of citrate. The present results support that as well with the concentration of acetate being greater in parthenogenetic than in the IVF embryos. These results are a first step in identifying noninvasive, quantitative parameters that indicate which embryos may be the most viable before transfer. Table 1.Results (least squares means ± s.e.)

In Vitro Fertilization and Risk of Autistic Disorder and Mental Retardation

The birth of the first infant conceived through in vitro fertilization(IVF)occurred35yearsago.1Theearlyfocusof IVFprograms wasonenhancingsuccessratesandoptimizingclinicalandlaboratory techniques inaneffort to improvechancesofpregnancy. Currently,morethan40%2ofyoungcouplesconceiveonasingle trial of IVF comparedwith less than 20% in the 1980s.3 In 2012, thenumberof infantsbornworldwideas a result of these technologieswas5million.Thesenumberswill continueto increase with 350 000 infants born annually as a result of an estimated 1.5million IVF cycles.4 The percentage of total births resulting from IVF is currently 1.4% (>60 000 infants/y) in the United States5and0.5%to4.4%(>100 000infants/y)inwesternEurope.6 Therefore, thesuccessof IVFsuggests it is important toshift the focus to the safety of the procedure for children. Pregnancies resulting from IVF differ from spontaneous conceptions in a number of ways that may affect health and welfare of children.Adverseoutcomeshavebeenmost clearly documentedfor risks relatedtoobstetricalandperinatalhealth, with increases in preterm delivery, low birth weight, neonatal admissions, and perinatal death.7,8 Additionally, data suggest an increased risk of congenital anomalies.8,9 However, it is unclear whether the increased risks are the result of the underlying infertility, specific parental factors, pregnancy multiplicity, oruniqueaspectsof theprocedures.10,11 Thishasbeen particularly true for neurodevelopmental disorders including autism spectrum disorders and mental retardation. Over the last 2decades, theprevalenceof autismspectrum disordershasincreased,yetthepathogenesisremainslargelyunknown. Increasingly, both genetic abnormalities and environmental stresshavebeen identifiedaspossible contributing factors. Increasedparentalage,12multiplebirth,pretermbirth,and lowbirthweight13,14areknownriskfactors forautism.ThesefactorsalsofrequentlycomplicateIVFpregnancies. Inaddition,concernshavebeen raisedabout theepigenetic risk thatmayoccur withboththeovarianstimulationandprolongedinvitroculture thatarepartof theIVFprocess.15Givenanevolvingtheoryabout theroleofepigenetics innormalbraindevelopment,16,17whether IVFmaybeplacing children at risk of neurodevelopmental abnormalities is an issue. Prior studieshavebeen largely reassuringregarding therisk ofautismfollowing IVF.18Mostof thesestudieshavecomefrom theScandinaviancountrieswherecountry-widedatabasesand registriesprovidepopulations forstudyandlinkagewith importantaspectsofboththeexposuresandoutcomesofinterest.However, these studies havebeen compromisedby relatively small samplesizes,poorlycharacterizedoutcomesof interest,andlimited specific details about IVF and the associated procedures. The studybySandinandcolleagues19 in this issueof JAMA hasseveralstrengthsthataddresstheseconcerns.Thestudy,conducted in Sweden, was population based and included a large number of children (2.5million, ofwhom6959had thenarrow diagnosisofautisticdisorderand15 830hadthediagnosisofmental retardation). Power therefore shouldhavebeenadequate to address thepotential associationbetween IVFandautistic disorderandmentalretardationandtoidentifywhetherspecific IVF procedures, particularly those that involvemoremanipulation of the egg andmale factor infertility, were associated with additional risk. The inclusionof all births in thepopulationeliminated the risk of selection bias. The linkagewith the IVF registry allowed identification of specific IVF procedures including intracytoplasmic sperm injection (ICSI) and identification of spermsource,alongwithwhether theembryosweretransferred onday3orday5inafreshorfrozencycle.Allof thesefactorsmay affectpregnancyandchildhoodhealth.Therewasexcellentconfirmationof theoutcomeof interest (autisticdisorderandmental retardation)becauseall children inSwedenundergoadevelopmentalassessmentandanyabnormalities requireevaluation bya specialized team.Despite these strengths, andeven in this largepopulation,as theanalyses focusedonspecific techniques andpatientpopulations, suchassurgicallyextractedsperm(the groupwiththehighestrisk),thenumbersofchildrenweresmall— particularly for affected individuals. The results of the study support the absence of an associationbetweenanyIVFprocedureandautisticdisordercompared with spontaneous conception (relative risk [RR], 1.14 [95% CI, 0.94-1.39]; 19.0vs 15.6per 100 000person-years).Althoughthe authors found a small risk ofmental retardation following IVF comparedwithspontaneouspregnancies (RR,1.18[95%CI, 1.011.36]; 46.3 vs 39.8 per 100 000 person-years), this increase becamenonsignificantwhenonlyevaluatingsingletonbirths (RR, 1.01 [95%CI,0.83-1.24]).Thiswasalso true for the identified increased risk of autistic disorder with the use of surgically extracted sperm (RR, 3.29 [95% CI, 1.58-6.87, 110.1 vs 30.9 per 100 000person-years] in all births;RR,0.73 [95%CI, 0.10-5.30, 18.3vs 24.3per 100 000person-years] in singletons). The identified riskswithsurgicallyextractedspermforbothautisticdisorderandmental retardationwere increasedfurtherbypreterm birth(forautisticdisorder,RR,8.06[95%CI,2.97-21.85]; formental retardation, RR 3.31 [95%CI, 1.18-9.31]). The association of multiple birth and preterm birth with these outcomes is particularly important because decreasing the number ofmultiple births is a primary goal of assisted reRelated article page 75 Opinion

Breastfeeding Multiples: It Can Be Done

The recognition of the benefits of breastfeeding and the perils of formula feeding makes it incumbent upon the nursing profession to become knowledgeable in the realm of evidence-based care for all breastfeeding women. This is even more apparent with the rise in the number of multiple births and the potential subsequent sequelae that frequently arises from multiple gestations, that is, preterm births. Breastfeeding organizations such as La Leche League promote and support breastfeeding for women with multiple births. The aim of this article is to address those issues that hinder a mother's desire to breastfeed her twins, triplets, or even quadruplets. The numerous benefits of breastfeeding are elucidated together with guidelines for the health care professional to use in assisting the breastfeeding mother.

Parental, Medical, and Sociological Responsibilities: “Octomom” as a Case Study in the Ethics of Fertility Treatments

The advent and development of various forms of fertility treatments has made the dream of parenthood concrete for many who cannot achieve it through traditional modes of conception. Yet, like many scientific advances, fertility treatments have been misused. Although still rare compared to the birth of singletons, the number of triplets, quadruplets, and other higher-order multiple births have quadrupled in the past thirty years in the United States, mostly due to the increasingly prevalent use of fertility treatments. In contrast, the number of multiple births has decreased in Europe in recent years, even though 54% of all assistant reproductive technology cycles take place in Europe, most likely because official guidelines have been implemented throughout several countries geared towards reducing the occurrence of higher-order multiple births.1 The gestation of multiple fetuses can result in dire consequences for them. They can be miscarried, stillborn, or die shortly after birth. When they do survive, they are often born prematurely and with a low birth weight, and may suffer from a lifetime of physical or developmental impairments. The objective of this paper is to explore the moral dimensions of certain uses of fertility treatments in light of the known dangers that may result from higher-order multiple births. I will do this by mainly focusing on the now infamous case of Nadya Suleman, also known as “Octomom.” I argue that Suleman and her fertility physician, Michael Kamrava, both violated important duties and virtues in the creation of her octuplets, but that my criticism of their actions equally applies to many other questionable uses of reproductive technology. Moreover, I will show that the responsibility for curbing the rise of high-order multiple births falls on the shoulders of not only patients and their doctors, but also the community of fertility physicians in general, insurance companies, and even the media.

Towards single embryo transfer? Modelling clinical outcomes of potential treatment choices using multiple data sources: predictive models and patient perspectives

In vitro fertilisation (IVF) treatments involve an egg retrieval process, fertilisation and culture of the resultant embryos in the laboratory, and the transfer of embryos back to the mother over one or more transfer cycles. The first transfer is usually of fresh embryos and the remainder may be cryopreserved for future frozen cycles. Most commonly in UK practice two embryos are transferred (double embryo transfer, DET). IVF techniques have led to an increase in the number of multiple births, carrying an increased risk of maternal and infant morbidity. The UK Human Fertilisation and Embryology Authority (HFEA) has adopted a multiple birth minimisation strategy. One way of achieving this would be by increased use of single embryo transfer (SET). To collate cohort data from treatment centres and the HFEA; to develop predictive models for live birth and twinning probabilities from fresh and frozen embryo transfers and predict outcomes from treatment scenarios; to understand patients' perspectives and use the modelling results to investigate the acceptability of twin reduction policies. A multidisciplinary approach was adopted, combining statistical modelling with qualitative exploration of patients' perspectives: interviews were conducted with 27 couples at various stages of IVF treatment at both UK NHS and private clinics; datasets were collated of over 90,000 patients from the HFEA registry and nearly 9000 patients from five clinics, both over the period 2000-5; models were developed to determine live birth and twin outcomes and predict the outcomes of policies for selecting patients for SET or DET in the fresh cycle following egg retrieval and fertilisation, and the predictions were used in simulations of treatments; two focus groups were convened, one NHS and one web based on a patient organisation's website, to present the results of the statistical analyses and explore potential treatment policies. The statistical analysis revealed no characteristics that specifically predicted multiple birth outcomes beyond those that predicted treatment success. In the fresh transfer following egg retrieval, SET would lead to a reduction of approximately one-third in the live birth probability compared with DET, a result consistent with the limited data from clinical trials. From the population or clinic perspective, selection of patients based on prognostic indicators might mitigate about half of the loss in live births associated with SET in the initial fresh transfer while achieving a twin rate of 10% or less. Data-based simulations suggested that, if all good-quality embryos are replaced over multiple frozen embryo transfers, repeated SET has the potential to produce more live birth events than repeated DET. However, this would depend on optimising cryopreservation procedures. Universal SET could both reduce the number of twin births and lead to more couples having a child, but at an average cost of one more embryo transfer procedure per egg retrieval. The interview and focus group data suggest that, despite the potential to maintain overall success rates, patients would prefer DET: the potential for twins was seen as positive, while additional transfer procedures can be emotionally, physically and financially draining. For any one transfer, SET has about a one-third loss of success rate relative to DET. This can be only partially mitigated by patient and treatment cycle selection, which may be criticised as unfair as all patients receiving SET will have a lower chance of success than they would with DET. However, considering complete cycles (fresh plus frozen transfers), it is possible for repeat SET to produce more live births than repeat DET. Such a strategy would require support from funders and acceptance by patients of both cryopreservation and the burden of additional transfer cycles. Future work should include development of improved clinical and regulatory database systems, surveys to quantify the extent of patients' beliefs and experiences and develop approaches to meet their information needs, and, ideally, randomised controlled trials comparing policies of repeated SET with repeated DET.

Effects of Progestagen and Pmsg on Estrous Synchronization and Fertility in Kivircik Ewes during Natural Breeding Season

An experiment was conducted using indigenous Kivircik ewes to evaluate the effect of intravaginal progestagen sponges, containing 30 mg of fluorogestone acetate (FGA), followed by administration of pregnant mare serum gonadotrophin (PMSG) on inducing synchronized oestrus in the season and fertility. Three times of PMSG administration relative to sponge withdrawal (24 h before (n = 30), at (n = 29) or 24 h after (n= 29)) and two routes of PMSG administration (intramuscular (n = 46) and subcutaneous (n = 42) were compared for estrous response, number of multiple births and fecundity rates. There were no significant differences in terms of estrous response, due to differences in the time and route of PMSG administration. Lambing percentage, proportion of multiple births and fecundity were 75.6, 51.6 and 114.6%, respectively. The administration had a significant effect on lambing (p<0.05), multiple birth and fecundity rates (p<0.01). The subcutaneous administration of PMSG resulted in a significantly higher lambing rate (p<0.05) and fecundity rate (p<0.01), compared to the intramuscular injection of the PMSG.

The effect of vitamin E treatment during preovulatory period on reproductive performance of goats following estrous synchronization using intravaginal sponges

The objectives of this study were to investigate whether the use of intravaginal sponge for estrous synchronization of goats causes oxidative stress, and to examine the effect of administering vitamin E during preovulatory period on reproductive performance of estrous synchronized goats. Estrus was synchronized in 36 non-lactating adult does using intravaginal sponges containing 30 mg of fluorogestane acetate (FGA) for 14 days. All females received 500 IU of eCG at the sponge withdrawal. The goats were allocated at random to two groups balanced for breed, age and body weight. Treatment group ( n = 18) received 200 mg of vitamin E i.m. at the time of sponge removal and again at the time of second artificial insemination. The other 18 goats (control) were administered 1 ml of physiological saline instead of vitamin E on each of these two occasions. All does in estrus was intracervically inseminated at 12 and 24 h after the onset of estrus. Blood samples were collected every 72 h during the experimental period for evaluation of malondialdehyde (MDA) and vitamin E concentrations. Serum MDA level increased and vitamin E concentration decreased during the period of vaginal sponge application. Following the sponge removal, MDA level declined rapidly to below basal level in the treatment group but remained high in the control group. Conversely, vitamin E concentration increased in the treatment group after the sponge withdrawal and remained at a low level in the control group. No statistically significant differences ( P > 0.05) were observed between groups in terms of estrous response, conception rate, gestation length or kidding rate. However, the number of multiple births (70.0% versus 50.0%) and prolificacy rate (2.40 ± 0.37 versus 1.63 ± 0.26 kids per kidding) were significantly higher ( P < 0.05) for the treatment group than those of the control group. The results indicate that the use of intravaginal sponges for estrous synchronization of goats causes an increase in level of oxidative stress. However, the vitamin E treatment during preovulatory period can prevent the overproduction of reactive oxygen species (ROS), and it may improve the multiple birth rates and the number of kids born in estrous synchronized goats.

The effect of reducing the number of embryos transferred on perinatal outcomes and total national multiple birth rates in Sweden 1991–2005

The effect of reducing the number of embryos transferred on perinatal outcomes and total national multiple birth rates in Sweden 1991–2005

Conséquences psychologiques des naissances multiples

Since the mid 1970s, the number of multiple births has dramatically increased in our country and most European countries. This paper summarizes the psychological consequences of multiple births based on a review of the literature and on our clinical experience. During pregnancy mothers experience great physical problems linked with increased medical risks for themselves and for the children. These risks cause psychological difficulties: hospitalisation and separation from the family, fear of a premature delivery and anxiety for the children. After delivery the children are often hospitalized, which makes the attachment process difficult. The mortality of multiple children is high and mourning for one child creates particular problems for parents who simultaneously face grieving and attachment processes. After hospital discharge, the overload of work mothers experience leads to physical and nervous fatigue, which does not make easier individual relationship with the children. Mothers have a high level of psychological vulnerability and an increased risk of depression. The satisfactory development of each twin or triplet child requires individualized relationship with his/her mother and his/her father. That is how he/she will be able to build his/her identity and future autonomy. It is important to be aware of the problems experienced by the families and to improve the way material help and psychological support are provided to them.

P-313: Elective embryo single transfer: How to select the best embryo?

Latin America Register of Assisted Reproduction data, in 2003, included twin or higher-order multiple gestation around 50.0%, mainly because more than 1 embryo has be transferred. Clearly, the most effective strategy for a reduction in the number of multiple births is to transfer a single embryo during a procedure. A number of non-invasive methods have been proposed to evaluate embryo viability in human IVF / ICSI programs. Based on this, efforts have been made to determine the main morphological non-invasive parameters able to select embryos with highest implantation potential to reduce the number of embryos transferred.

Primary Care for Twins and Higher Order Multiples

Despite the staggering increase in the number of multiple births, most primary care physicians have received little if any training in how to provide care for multiple-birth children and counseling for parents of multiples. Although the upsurge in multiple births has spawned a plethora of magazine stories, books, and web sites about the experiences of families with multiple-birth children, relatively few well-researched and sound resources exist to guide health care professionals in providing care and practical advice to families with twins. As general pediatricians and mothers of twins, we have searched to find answers to our questions about caring for and parenting twins. In this article we bring together material from diverse sources to provide an overview of issues specific to families with multiple-birth children that may be of particular importance in the primary care setting. We have focused primarily on families with twins, although we have made occasional references to triplets and higher order multiple births. We will address the following subjects in greater depth: The recent rise in the number and rate of multiple births is largely due to two factors: the increasing number of births among older women and greater use of fertility-enhancing therapies. Although the increase in the rate of twin births is most dramatic among mothers 45 years of age or older, nearly 75% of twins are born to women between 25 and 39 years of age. Most of the increase in the rate of twin births is due to an increase in the number of dizygotic twins. Higher neonatal and infant mortality and morbidity rates among twins are due to higher prevalence of prematurity and low birth weight, but also result from hemodynamic imbalances via placental anastomoses in monozygotic twin pregnancies. Feeding is particularly stressful for many mothers of twins. We review advantages and disadvantages of breastfeeding, combining breast- and bottle-feeding, and exclusively bottle-feeding twins. We present practical suggestions for successfully breastfeeding twins, including when a breast pump may be helpful and what types of breast pumps may be most useful. Many parents feed their twins simultaneously to save time. To avoid bottle-propping, we provide suggestions about positions for simultaneously breastfeeding or bottle-feeding twins. In general, twins progress in their motor and cognitive development like singletons of the same gestational age. Twins may lag slightly behind their singleton counterparts in language development. At 3 years of age, twins who use “private language” (ie, communication directed exclusively to the other sibling that is not used with anyone else and is not understood by

The impact of multiple preterm births on the family.

As the number of multiple births has steadily risen over the past 20 years, twins and triplets form an increasingly large proportion of the preterm population. This causes a number of stresses to their families. Addressing the cause of the epidemic of iatrogenic multiple births is the most effective way to reduce the number of preterm infants and the long-term problems to which they are prone.

UAPs and Breastfeeding

The recognition of the benefits of breastfeeding and the perils of formula feeding makes it incumbent upon the nursing profession to become knowledgeable in the realm of evidence-based care for all breastfeeding women. This is even more apparent with the rise in the number of multiple births and the potential subsequent sequelae that frequently arises from multiple gestations, that is, preterm births. Breastfeeding organizations such as La Leche League promote and support breastfeeding for women with multiple births. The aim of this article is to address those issues that hinder a mother's desire to breastfeed her twins, triplets, or even quadruplets. The numerous benefits of breastfeeding are elucidated together with guidelines for the health care professional to use in assisting the breastfeeding mother.

Optimum use of subcutaneous melatonin implants to enhance the reproductive performance of seasonal and non-seasonal sheep joined in spring and early summer

This paper reviews data from five research trials and 108 clinical trials conducted in three countries to validate the optimum use of melatonin to advance seasonal breeding patterns of a variety of breeds of sheep. In order to define the optimum time for treatment in breeding flocks, ewes of three different breeds were treated with controlled-release 18-mg melatonin implants (Regulin®), with treatments commencing at various times ranging from 9 to 3 weeks prior to joining with fertile rams. Mating and conception patterns were recorded by regular observation for raddle marks and fecundity was assessed by mid-pregnancy ultrasonography. These research trials were conducted at a latitude of 38°S in Merino ewes of slight seasonality, in Merino-based cross-breeds of intermediate seasonality and in highly seasonal British breed Romney Marsh ewes. A single implant treatment, commencing at 30–40 days prior to spring or early summer joining, resulted in coincidence in timing of the peak of the inductive phase of the ovarian response to melatonin with the peak of oestrus and mating which arose from the pheromonal influence of the rams. Thus, this treatment strategy maximises the potential advantages to be obtained from both the melatonin treatment and the rams. Subsequent clinical trial programmes in Australia, the UK and New Zealand confirmed this treatment strategy and tested the available periods of the year during which effective responses could be obtained under farm conditions. It was shown that, whereas Merino and Merino cross-breeds were responsive to melatonin treatment over a wide part of spring and early summer, the British breed ewes responded only during a relatively short period of the season around the time of the summer solstice. Treatments which commenced too early in British breeds were ineffective or gave negative results, possibly because of a failure of such breeds to be able to fully interpret the pharmacological short-day signal before they have experienced an adequate period of long-day priming. For all breeds, treatments given late in summer at a time of decreasing natural daylight were also ineffective since, by this time, ewes were already experiencing a naturally occurring inductive photoperiodic signal. Overall, the studies reviewed in this paper showed that melatonin pretreatment of spring and early summer joined ewe flocks resulted in both a modest decrease in the number of barren ewes and an increase in the number of multiple births. The effects were seen in flocks of high or low basal performance and in both maiden and mature ewes, but in no case were the responses associated with the induction of supraphysiological litter size. Mean increases in litter size, for different breeds of ewe, ranged from 14.3 to 28.6 additional lambs born per 100 ewes treated, with variation between trials largely accounted for by expected sampling errors associated with the precise measurement of the discontinuous variable of litter size in relatively small sample sizes of 50–200 animals per group. Treatment of mothers with melatonin prior to joining had no effect on the sex ratio, birth weight or appearance of offspring. Melatonin pretreatment of breeding ewes was also associated with an earlier mean conception (lambing) date and a compaction of the conception (lambing) patterns but the magnitude of these measured effects was dependent upon the extent to which untreated control flocks were responsive to the pheromonal influence of rams. Overall the data extends, to a practical field level, the proper use of melatonin to at least partially overcome the seasonal constraint to breeding in sheep, and provides a sound basis for future research and clinical experimentation in this area.

A note on the effect of tail-tying on the reproductive performance of Welsh Mountain ewes

SUMMARYIn a Welsh Mountain flock of 104 ewes, 51 had their tails tied aside for the duration of one oestrus. Tail-tying significantly increased the conception rate at this oestrus. It also significantly increased the mean litter size of ewes superovulated with 1000IU PMSG from 1·70 to 2·33. It is suggested that the most likely reason for this increase in the number of multiple births was an increased number of ejaculations per oestrus. Perinatal mortality was high in lambs from multiple births. The effect of PMSG and tail-tying was to increase the lambing percentage from 77 to 120.

THE BIRTH OF SIX PAIRS OF FRATERNAL TWINS TO THE SAME PARENTS

The literature contains numerous reports of women who have had a large number of multiple births. Probably the most frequently cited is that mentioned by Geissler 1 concerning Mary Austin, who, during thirty-three years of married life, is said to have borne forty-four children, thirteen pairs of twins and six sets of triplets. One sister of this mother is reported to have had twenty-six children and another forty-one. In addition to what must have been her principal occupation. Mary Austin apparently found time to acquire a doctor's degree. An even more remarkable case is that reported by Boer 2 of a Viennese woman who bore thirty-two children in eleven births. In the third month of her twelfth pregnancy her abdomen was described as being as large as that of a normal woman at term. This reference to the size of her abdomen suggests that she was well on the way