Incidence Of Twin Pregnancies Research Articles

Chorionicity and mode of fertilization: a long‐standing misconception

Chorionicity and mode of fertilization: a long‐standing misconception

Respiratory function in singleton and twin pregnancy.

Singleton pregnancy causes important changes in respiratory function. The incidence of twin pregnancies is increasing, but it is not known whether affected women suffer greater respiratory compromise. The aim of this study was to determine if changes in respiratory function during pregnancy in healthy women were greater in those with a twin pregnancy compared with those with a singleton pregnancy. Cross sectional study. London teaching hospital. Healthy pregnant women attending the antenatal clinic and ultrasound department. A cross sectional study of respiratory function was performed in 68 women with twin pregnancies (17 examined in the first trimester, 35 second trimester, 16 third trimester) and 140 women with singleton pregnancies (28, 80, 40, respectively) and 22 non-pregnant women. Women were examined once between 7 and 40 weeks of gestation. Forced vital capacity, relaxed vital capacity, forced expiratory volume in 1 second (FEV1), peak flow, inspiratory capacity, functional residual capacity (FRC), expiratory reserve volume, pulmonary diffusing capacity and minute ventilation were measured. Both in twin and singleton pregnancies, the mean FRC and expiratory reserve ventilation of women studied in the third trimester and minute ventilation of women studied in each trimester differed significantly from that of the non-pregnant women. There were, however, no significant differences demonstrated in respiratory function between healthy women with twin as compared with singleton pregnancies. In healthy women, the extra demands of atwin compared with a singleton pregnancy do not compromise further the respiratory system.

Respiratory function in singleton and twin pregnancy

Objective Singleton pregnancy causes important changes in respiratory function. The incidence of twin pregnancies is increasing, but it is not known whether affected women suffer greater respiratory compromise. The aim of this study was to determine if changes in respiratory function during pregnancy in healthy women were greater in those with a twin pregnancy compared with those with a singleton pregnancy. Design Cross sectional study. Setting London teaching hospital. Population Healthy pregnant women attending the antenatal clinic and ultrasound department. Methods A cross sectional study of respiratory function was performed in 68 women with twin pregnancies (17 examined in the first trimester, 35 second trimester, 16 third trimester) and 140 women with singleton pregnancies (28, 80, 40, respectively) and 22 non-pregnant women. Women were examined once between 7 and 40 weeks of gestation. Forced vital capacity, relaxed vital capacity, forced expiratory volume in 1 second (FEV1), peak flow, inspiratory capacity, functional residual capacity (FRC), expiratory reserve volume, pulmonary diffusing capacity and minute ventilation were measured. Results Both in twin and singleton pregnancies, the mean FRC and expiratory reserve volume of women studied in the third trimester and minute ventilation of women studied in each trimester differed significantly from that of the non-pregnant women. There were, however, no significant differences demonstrated in respiratory function between healthy women with twin as compared with singleton pregnancies. Conclusion In healthy women, the extra demands of a twin compared with a singleton pregnancy do not compromise further the respiratory system.

Twin delivery

The incidence of twin pregnancy has increased worldwide over the past 10 years largely as a consequence of the assisted reproductive technologies. Issues such as intrapartum monitoring and operative interventions, especially with regard to the second twin, provide a unique challenge in labour and delivery. Epidemiological data suggest that the term twin has a threefold higher mortality rate than the singleton. It is the authors' view that many aspects of twin delivery deserve as much import as those features of twin gestations such as pre-term birth and intrauterine growth restriction that, to date, have received much of the research and clinical interest in this area.Indications for elective Caesarean section are presented, incorporating new data derived from the delivery of the term singleton breech, and implications on the timing thereof are discussed.Vaginal delivery of both twins presenting by the vertex is recommended as safe as long as guidelines for the conduct of such delivery are followed. The recommended time interval between twins as well as the use of epidural, fetal monitoring and ultrasound in the delivery room are discussed.The second twin presenting as a non-vertex presents an urgent dilemma for accoucheurs. Data suggest that internal version and breech extractions are safer than external cephalic version provided that the appropriate techniques are applied. It is revealed, however, that the use of elective Caesarean section in this group of babies has not been subject to randomized controlled studies of sufficient power to determine the best method of delivery of the second twin – particularly in the low-birth-weight baby.

Outcome of twin pregnancies in North Jordan

In a retrospective study we examined the outcome of twins delivered at Princess Badee'a Teaching Hospital from 1 January 1996 to 30 June 1999. The incidence of twin pregnancy was 1/86 with a gross perinatal mortality rate of 178 per 1000. Breech presentation was associated with the highest perinatal mortality rate (278 per 1000). One hundred and eighty-four out of the 386 twin pregnancies were preterm with the highest perinatal mortality rate (184 per 1000). The neonatal Mortality rate fell with increasing birthweight from 532 per 1000 at 1500g to 16 per 1000 at 2500g. Our results showed that the risk factors were mainly prematurity, low birthweight, pregnancy-induced hypertension, lack of proper antenatal care, birth asphyxia, and malpresentation.

Perinatal morbidity and mortality rates in twin pregnancies--a 15-year review study from Athens.

There were 150 deliveries of twin pregnancies over 26 weeks in our hospital. The incidence of twin pregnancies was 1.0% in a population consisting of Greek nationals. Seventy five (50%) were term at delivery whereas 75 (50%) were premature (mean gestational age at delivery 36.5 weeks). The birth weight at delivery ranged from 350 grs to 4,050 grs with mean birth weight for the 1st and 2nd twin of 2,404 grs and 2,384 grs, respectively. One hundred and forty four (48%) neonates had weights between 1,501 to 2,500 grs. Twenty two (9.57%) neonates had weights between 1,501 grs to 2,500 grs. The perinatal mortality when birth weights exceeded 1,500 grs was 7.32%. In total, 186 (62%) newborns were delivered vaginally and 114 (38%) by cesarean section. Forceps were used in 4.33% of the cases and breech extraction was performed in 2.33%. The mode of delivery and perinatal mortality rates were not correlated for both twins (p > 0.05). The most common causes of death were hyaline membrane disease (48.5%), immaturity (18.2%), congenital abnormalities (15.1%), septicemia (12.1%) and asphyxia (6.06%). Prematurity seems to constitute the most common cause of perinatal deaths while the mode of delivery found to be irrelevant to perinatal mortality.

Fetal testing in twins

The incidence of twin pregnancies continues to rise with increasing use of assisted fertility techniques. The search for accurate methods of chorionicity determination and aneuploidy screening, and the outcome following multi-fetal pregnancy reduction dominate the recent literature. In addition, debate on the aetiology and management of the transfusional complications of monochorionicity continues.

Frequency of Twin Pregnancies Following Renal Transplantation

Objective: To evaluate the incidence of twin pregnancy among renal-transplanted women.Methods: A retrospective review based on three national inquiries. A computer literature search of the Medline system was done. Only reports of series were included. For statistical analysis the probability of having a twin pregnancy was assumed to be 0.012.Main Outcome Measures: Incidence of twin pregnancy in women after renal transplantation.Results: There were 7 sets of twins among 153 pregnancies reported in the national inquiry group (4.57%). Thus, the overall incidence of twin pregnancy in these women was 1 in 22 pregnancies. The frequency of twinning in series reporting pregnancies after renal transplantation was 1.84%, a figure statistically greater than the expected number of twins (P = 0.001).Conclusions: The frequency of twin pregnancy appears to be increased among renal-transplanted women.

Surveillance of Bromocriptine in Pregnancy

Information was collected on the outcome of 1,410 pregnancies in 1,335 women to whom bromocriptine mesylate (Parlodel) had been given, primarily in the early weeks of pregnancy. These pregnancies resulted in 197 early terminations (14%) (including 25 induced abortions [1.8%]) and in 1,213 births (86%). The incidence rate of spontaneous abortions (11.1%), extrauterine pregnancies (0.9%), and minor (2.5%) and major (1.0%) malformations is comparable with that quoted for normal populations, and the incidence of twin pregnancies (1.8%) is slightly but not significantly raised, if correction is made for concomitant therapy with other agents inducing ovulation. The data suggest that the intake of bromocriptine during pregnancy is not associated with an increased risk to the fetus. ( JAMA 1982;247:1589-1591)

Surveillance of Bromocriptine in Pregnancy

Information was collected on the outcome of 1,410 pregnancies in 1,335 women to whom bromocriptine mesylate (Parlodel) had been given, primarily in the early weeks of pregnancy. These Pregnancies resulted in 197 early terminations (14%) (including 25 induced abortions [1.8%) and in 1,213 births (86%). The incidence rate of spontaneous abortions (11.1%), extrauterine pregnancies (0.9%), and minor (2.5%) and major (1.0%) malformations is comparable with that quoted for normal populations, and the incidence of twin pregnancies (1.8%) is slightly but not significantly raised, if correction is made for concomitant therapy with other agents inducing ovulation. The data suggest that the intake of bromocriptine during pregnancy is not associated with an increased risk to the fetus.

Perinatal factors and neonatal morbidity in twin pregnancy

There were 177 pairs of twins reviewed. The incidence of twin pregnancy was 1:112.2 deliveries in a population consisting of 76.8 per cent Mexican-Americans. The incidence of breech, cesarean section, and assisted deliveries was higher in twins than singleton deliveries, and the incidence was higher in twin 2 than twin 1. Mortality rates, fetal and neonatal, were lower than those previously reported. Neonatal findings and complications include low Apgar scores, small-for-dates infants, hyaline membrane disease, hypoglycemia, hypocalcemia, hyperbilirubinemia, and congenital malformation. The increased incidence of deaths and morbidity in twin pregnancy, as compared to singleton pregnancy, was attributed to prematurity, and to complications and diseases pertaining to prematurity, rather than to twinning per se.

The significance of anemia in an obstetric population in Australia.

SummaryIn a series of 15 321 consecutive patients 568 (3.7 per cent) had haemoglobin values below 9.2 g. per 100 ml. before delivery. The commonest causes of amaemia were iron deficiency (49 per cent) and β‐thalassaemia minor (28 per cent), the latter being explained by a high proportion of patients of Mediterranean origin. The most important cause of anaemia, in terms of maternal morbidity and perinatal mortality, was chronic renal disease which had an incidence of 7 per cent (39 of 568). Maternal age and parity were significantly higher in the anaemia series than in a control series of non‐anaemic patients. The incidence of twin pregnancy was 5.2 per cent or five times that of whole obstetric population.Maternal oestriol excretion was low in 24 per cent of anaemic patients tested (55 of 225), including 12 of 13 patients tested whose infants died. The association between maternal anaemia and placental hypertrophy was confirmed.In the whole anaemia series the perinatal mortality rate was 3.8 per cent, and it was 6.4 per cent (13 of 202) in patients with haemoglobin values below 8.2 per 100 ml. Patients with anaemia who were most likely to have perinatal deaths were those with associated chronic renal disease. Renal function tests should be performed during pregnancy when anaemia is severe of fails to respond to treatment.