Placental Delivery Research Articles

Manual removal or spontaneous placental delivery and postcesarean endometritis and bleeding

Objectives: To compare the effect of manual removal and spontaneous delivery of placenta on postcesarean bleeding and endometritis. Methods: In this prospective study 400 pregnant women undergoing elective cesarean delivery were randomly assigned to two groups: spontaneous placental delivery (200 women) and manual placental delivery (200). No antibiotic prophylaxis was administered in either group. The significance of blood loss due to cesarean delivery was defined by a drop in hemoglobin concentration of more than 1 g/dl 24 h after delivery in comparison with preoperative hemoglobin concentration. Endometritis was diagnosed in patients who developed clinical signs of fever and suprapubic tenderness 48 h after delivery. We analyzed the data using a t-test. Results: The overall endometritis rate was 27%, in 40 women in the spontaneous placental delivery group (20%) and 68 women in the manual placental removal group (34%). There was a statistically significant difference between the two groups ( P=0.001). Significant blood loss was experienced by 52 women (26%) in the spontaneous placental delivery group vs. 100 women (50%) in the manual placental delivery group. There was a statistically significant difference in blood loss between the two groups ( P=0.000; RR=1.92). Conclusion: Endometritis and blood loss in cesarean delivery is increased by manual removal of the placenta compared with the spontaneous method of placental removal.

Greater vascularity, lowered HIF-1/DNA binding, and elevated GSH as markers of adaptation to in vivo chronic hypoxia.

Vascularity is increased in placentas from high- compared with low-altitude pregnancies. An angiogenic response to hypoxia may protect an organ from further hypoxic insult by increasing blood flow and oxygen delivery to the tissue. We hypothesized that increased placental vascularity is sufficient to adapt to high altitude. Therefore, indexes of hypoxic stress would not be present in placentas from successful high-altitude pregnancies. Full-thickness placental biopsies were 1) collected and frozen in liquid nitrogen within 5 min of placental delivery and 2) fixed in formalin for stereologic analyses at high (3,100 m, n = 10) and low (1,600 m, n = 10) altitude. Hypoxia-inducible transcription factor (HIF-1) activity was analyzed by ELISA. Western blot analyses were used to evaluate HIF-1alpha, HIF-1beta, HIF-2alpha, von Hippel-Lindau protein, VEGF, Flt-1, enolase, and GAPDH. Magnetic resonance spectroscopy was used to evaluate endogenous metabolism. The ratio of placental capillary surface density to villous surface density was 70% greater at high compared with low altitude. HIF-1 activity and HIF-1-associated proteins were unchanged in placentas from high- vs. low-altitude pregnancies. Placental expression of HIF-1-mediated proteins VEGF, Flt-1, enolase, and GAPDH were unchanged at high vs. low altitude. Succinate, GSH, phosphomonoesters, and ADP were elevated in placenta from high compared with low altitude. Placentas from uncomplicated high-altitude pregnancies have greater vascularity and no indication of significant hypoxic stress at term compared with placentas from low altitude.

Childbirth and Myoma Treatment by Uterine Artery Occlusion: Do They Share a Common Biology?

When the uterine arteries are bilaterally occluded, either by uterine artery embolization or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic. It is postulated that myomas are killed by the same process that kills trophoblasts: transient uterine ischemia. When the uterine arteries are bilaterally occluded, either by uterine artery embolization (UAE) or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic. Over time, stagnant blood in these arteries and veins clots. Then, tiny collateral arteries in the broad ligament (including communicating arteries from the ovarian arteries) open, causing clot within myometrium to lyse and the uterus to reperfuse. Myomas, however, do not survive this period of ischemia. This is unique organ response to clot formation and ischemia. What allows the uterus to survive a relatively long period of ischemia while myomas perish? Childbirth appears to be the predicate biology. Following placental separation, the uteroplacental arteries and the draining veins of the placenta are torn apart at their bases in the junctional zone of the myometrium and bleed directly into the uterine cavity. Left unchecked, every woman would bleed to death in less than 10 minutes after placental delivery. Most women do not bleed to death because vessels in the uterus clot after placental delivery. During pregnancy, clotting and lytic factors in blood increase many fold. Following delivery, uterine contractions continue, intermittently, periodically slowing the velocity of flowing blood through myometrium. The combination of slowed blood flow, elevated clotting proteins, and torn placental vessels (known as Virchow's triad) causes blood in myometrial arteries and veins to clot. 1 Fibrinolytic enzymes later lyse clot in arteries and veins not associated with placenta perfusion, and the uterus is reperfused. Remnant placental tissue—primarily uteroplacental arteries and veins—does not survive this period of ischemia. Placental tissue dies and over weeks is sloughed into the uterine cavity. At the same time, residual endometrial tissue grows under the sloughing placental tissue thus re-establishing the endometrial lining. It is postulated that myomas are killed by the same process that kills trophoblasts—transient uterine ischemia. 2

Comparison of Carbetocin and Oxytocin for the Prevention of Postpartum Hemorrhage Following Vaginal Delivery: A Double-Blind Randomized Trial

Objectives: To compare the efficacy of a single 100 µg intramuscular (IM) carbetocin injection, a long-acting oxytocin agonist, to a 2-hour 10 IU oxytocin intravenous (IV) infusion, in reducing the incidence and severity of postpartum hemorrhage (PPH) in women at risk for this condition.Methods: A randomized, double-blind, placebo-controlled study was conducted at 2 hospital centres, including 160 women with at least I risk factor for PPH. Eighty-three women received 100 µg carbetocin IM and an IV placebo immediately after placental delivery, while 77 women received placebo IM and oxytocin IV infusion. Complete blood count was collected at entry and 24 hours postpartum. All outcome measures, including the need for additional uterotonic agents or uterine massage, blood loss, and drop in hemoglobin and hematocrit, were analyzed using chi-square, Fisher exact, and Student t tests.Results: Population profile and risk factors for PPH were similar for each group. No significant difference was observed in the number of women requiring additional uterotonic medication (12 in each group). However, in the carbetocin group, 36 of the 83 women (43.4%) required at least I uterine massage compared to 48 of the 77 women (62.3%) in the oxytocin group (P < .02). Overall, uterotonic intervention was clinically indicated in 37 of the women (44.6%) receiving carbetocin compared to 49 of the women (63.6%) given an IV oxytocin infusion (P < .02). There were no differences in laboratory PPH indicators between the 2 groups.Conclusions: Women receiving a single 100 µg IM carbetocin injection required significantly less uterotonic intervention compared to women receiving a continuous 2-hour IV oxytocin infusion. A single IM carbetocin injection is more likely to prevent PPH in women at risk when compared to a continuous oxytocin IV infusion.

Randomized controlled trial of misoprostol for second-trimester pregnancy termination associated with fetal malformation

Objective Our purpose was to compare the effectiveness, women's views of the termination procedure, and success of umbilical cord culture for vaginal and oral misoprostol versus intra-amniotic prostaglandin PGF 2α for second-trimester pregnancy termination (STPT). Study design We randomized 217 women, 15 to 24 weeks' gestation, into 3 groups. Oral (OM) and vaginal (VM) misoprostol groups received 400 μg of misoprostol every 4 hours for 24 hours. The intra-amniotic PGF 2α (IAPG) group received 40 mg of PGF 2α followed by oxytocin infusion. Women completed self-administered questionnaires 3 weeks after the termination procedure. Umbilical cord samples were collected at delivery for karyotype analysis. The primary outcome was the time from start of the procedure to placental delivery. Secondary outcomes were maternal complications, women's acceptance of the termination procedure, and success rates of umbilical cord culture. Results The time was longer for the OM group (30.5±14.4 hours) compared with the VM group (18.3±8.2 hours) and the IAPG group (21.1±10.2 hours), P<.001 for both comparisons. Women in the VM group reported being more willing to repeat the termination method in the future and reported fewer side effects than those in the other groups, P<.001. Failure rates for umbilical cord cultures were 9.6%, 17.0%, and 45.6% for the VM, OM, and IAPG groups, respectively. Conclusion Oral misoprostol is less effective than intra-amniotic PGF 2α or vaginal misoprostol for STPT. Women report vaginal misoprostol more acceptable than other methods. Umbilical cord culture failure rate is highest in the IAPG group.

Prostaglandin mediates premature delivery in pregnant sheep induced by estradiol at 121 days of gestational age.

The experiments reported here were designed for both in vivo and in vitro approaches in the same animals to obtain a better picture of the role of estrogen in the control of parturition. Chronically catheterized pregnant ewes were treated with vehicle (n = 5) or estradiol (n = 6), 5 mg twice a day, im for 2 d starting at d 119 of gestation. Maternal and fetal plasma estradiol, progesterone, and cortisol were measured by RIA and maternal plasma prostaglandin (PG) F2alpha was measured by enzyme immunoassay. Intrauterine PG H synthase 2 mRNA and protein and placental P450(c17)alpha hydroxylase mRNA were determined by Northern, in situ hybridization, Western blot analysis, and immunocytochemistry. Data were analyzed by ANOVA. Five of six estradiol-treated ewes delivered their fetuses within 48 h; however, the placenta was still retained 5-6 h after fetal delivery. Both maternal plasma estradiol and PGF2 alpha increased significantly in the estradiol-treated group. Maternal and fetal plasma progesterone and cortisol were not altered in either group. There were significant increases of PGH synthase 2 mRNA and protein in myometrium, endometrium, and maternal placenta but not in fetal placenta in estradiol-treated ewes. Placental P450(c17)alpha hydroxylase mRNA was not detectable in vehicle or estradiol-treated groups. Estradiol can, in the absence of increase in plasma cortisol, stimulate uterine PG production and induce labor, resulting in fetal delivery in the sheep. Failure of placental delivery after estradiol treatment suggests that estradiol alone is insufficient to stimulate some of the key changes required to complete delivery at the stage of gestation studied.

Clinical observation of blood loss reduced by tranexamic acid during and after caesarian section: a multi-center, randomized trial

Objectives: To explore the efficacy and safety of tranexamic acid at caesarian section (CS). Study design: Prospective, randomized, case-controlled clinical trial. Population: One hundred and eighty primiparas were randomized into two groups. The study group, 91 women, received tranexamic acid immediately before CS whereas the control group, 89 women did not. Method: Blood was collected during two periods. The first period was from placental delivery to the end of CS and the second was from the end of CS to 2 h postpartum. The quantity of blood was measured and compared between the two groups. Complete blood count, urinalysis, liver and renal function, prothrombin time and activity, were tested in the two groups. Results: Tranexamic acid significantly reduced the quantity of blood from the end of CS to 2 h postpartum: 42.75±40.45 ml in the study group versus 73.98±77.09 ml in the control group ( P=0.001). It also significantly reduced the quantity of total blood from placental delivery to 2 h postpartum: 351.57±148.20 ml in the study group, 439.36±191.48 ml in the control group ( P=0.002). No complications or side effects were reported in either group. Conclusions: Tranexamic acid statistically reduces the extent of bleeding from placental delivery to 2 h postpartum and its use was not associated with any side effects or complications. Thus, tranexamic acid can be used safely and effectively to reduce bleeding resulting from CS.

Estimation of time of fetal death in the second trimester by placental histopathological examination.

It has been suggested that certain placental histopathological changes may be useful in predicting the time of death in stillborn fetuses. We retrospectively evaluated 36 placentas from therapeutic terminations in which the time interval between fetal death and delivery was relatively short and well-documented to determine the earliest stillbirth-associated changes and the utility of placental examination in timing death in the second trimester. In each case, termination had been initiated by creating fetal asystole with intracardiac KCl injections. The gestational age ranged from 18-23 wk. The time from asystole to placental delivery range was 2.8-52.0 h. Placental groups were categorized by time intervals from asystole to delivery: I, <12 h [n = 4 (11%)]; II, 12-24 h [n = 15 (42%)]; III, 24-36 h [n = 14 (39%)]; IV, > 36 h [n = 3 (8%)]. Among eight histopathologic changes involving the umbilical cord or chorionic villi evaluated, only three were present in a significant number of cases and also appeared to be the result of stillbirth. Degeneration of cord vascular smooth muscle was present in 33% of umbilical cords in group I, but was seen in 100% of cords in groups II-IV; the extent of these changes increased significantly with increasing time intervals. Intravascular karyorrhexis was present in villous blood vessels in 75, 73, 64, and 100%, respectively, for groups I-IV. Villous blood vessel luminal abnormalities were seen in 25, 7, 21, and 67%, respectively, for groups I-IV. These findings indicate that these are the earliest morphological changes in stillbirth in second trimester placentas, but they cannot be used to accurately predict time of death in the relatively short time intervals evaluated in this study.

The Effect of Placental Delivery Method During Elective Cesarean Delivery on Blood Loss and Endometritis

The Effect of Placental Delivery Method During Elective Cesarean Delivery on Blood Loss and Endometritis

The effect of placental delivery method during elective cesarean delivery on blood loss and endometritis

The effect of placental delivery method during elective cesarean delivery on blood loss and endometritis

Metabolite Concentrations in Human Term Placentae and Their Changes Due to Delayed Collection After Delivery

The present study was designed to quantify the major cellular metabolites in human placentae and their changes due to the confounding effect of time and subsequent hypoxia during sample collection using magnetic resonance spectroscopy (1H-and 31P-MRS). The absolute placental concentrations of lactate, glucose, major amino acids and cellular volume/osmo-regulators, glutathione, high-energy phosphates, fatty acids, phospholipids, triglycerols, and cholesterol are reported. There were no spatial differences in metabolism or protein expression throughout the placenta. The most significant temporal changes, due to the collection time (from 1 to 25min after delivery), were increased concentrations of lactate (r=0.996, statistically significant P< 0.01 after 11min) and decreased concentration of glucose and ATP (r=−0.963 and −0.97, respectively, P< 0.01 after 11min). The placental samples from the later collection groups (16–24min) had also significantly lower level of NAD+ (r=−0.95, P< 0.01). Only the latest collection group (21–24min) had increased lipid peroxidation and changes in lipid metabolites (P< 0.01). We conclude that the optimal window for collecting placental tissue without incurring metabolic artifacts due to hypoxic conditions is within 9min of placental delivery.

Comparison between two cord blood collection strategies

Background and objectives. Collection strategy is the first step for collecting good quality cord blood (CB) units. There are two principal different techniques to collect CB from the umbilical vein: in the delivery room while the placenta is still in the uterus by midwives and obstetricians or in an adjacent room after placental delivery by CB-bank trained personnel. In this study, the benefits and disadvantages between two different CB collection strategies were evaluated in order to improve CB bank methodology. Design and methods. Valencia CB bank maintains the two different collection strategies aforementioned. Before processing CB units, volume was calculated and samples were drawn for cell counts. After processing and before cryopreservation, samples for cell counts, CD34 analysis, viability, clonogenic assays and microbiology were drawn directly from the bags. We compared the efficiency of the two collection techniques. Results. Obstetric date and umbilical CB was obtained from 848 vaginal (484 collected in uterus and 364 collected ex uterus). The proportion of excluded CB units before processing was 33% for ex uterus and 25% for in uterus. The difference was statistically significant. A larger volume and a higher number of total nucleated cells, CD34+ cells and CFUs were harvested in the in uterus collection group. Interpretation and conclusions. Based on our findings, we conclude that the mode of collection influences the hematopoietic content of CB donations. Collection before placental delivery is the best approach to CB collection and allows optimizing CB bank methodology.

Differences in Umbilical Cord Blood Units Collected during Cesarean Section, before or after the Delivery of the Placenta

Umbilical cord blood is largely employed as an alternative source of stem cells in the treatment of hemato-oncological diseases. Current results show that the success rate of purified umbilical cord blood engraftment is comparable to that obtained using bone marrow, and it is directly related to the number of pluripotent stem cells transplanted. The technique of fetal blood collection varies among different umbilical cord blood banks. Many authors collect umbilical cord blood during vaginal delivery, after placental detachment, while others collect it while the placenta is still within the uterus. In a previous randomized trial, we showed a greater collection of umbilical cord blood before placental detachment during vaginal delivery. The present study was performed to determine whether umbilical cord blood collection before placental detachment (group A) during cesarean section is superior to that after placental delivery (group B) puncturing the umbilical vein once and using a closed bag system. To accomplish this, 47 pregnant women subjected to cesarean section were enrolled in the study. Twenty-one of them were allocated to group A, while the remaining 26 formed group B. The volume of umbilical cord blood collected from the patients of group A was greater than that collected from patients of group B. The cord blood volume collected was 90.7 ± 6.0 versus 60.9 ± 13.7 ml; the cord blood nucleated cell number was 10.1 ± 1.2 × 10⁸ vs. 7.1 ± 0.8 × 10⁸; and the mean cord blood CD34+ cell number was 20.0 ± 6.0 × 10⁵ vs. 16.4 ± 2.4 × 10⁵, respectively.

Quantificação dos níveis de endotelina-1 em placentas e mebranas fetais humanas

The endothelin is a potent vasoconstricor that possess angiogenic, mitogenic and neurotrophical functions. In this study we aimed to quantify the Endothelin-1 (ET-1) levels in chorionic placental villi and amnion of placentae of twins childbirths whose women were submitted to an assisted pregnancy and spontaneal fecundation. Were collected 08 placental samples. After the placental delivery the samples had been placed in liquid nitrogen and later in a -80oC until the Enzyme-Linked Immunosorbent Assay (ELISA) technique. The concentration levels of ET-1 in samples of chorionic villi in twins placentae varied from 0,52 to 0,70 fmol/ml, while in chorionic villi single gestation varied from 0,47 to 0,86 fmol/ml. The same determination in samples of amnion of twins placentae varied from 0,65 to 1,16 fmol/ml, while in single gestation varied from 0,65 to 1,04 fmol/ml. These findings suggests that in the chorionic villi the levels of ET-1 didn't vary between twins and single gestation. In the amnion the levels of ET-1 are higher in twins than in single gestation, suggesting that the amnion is the source of ET-1 in the amniotic fluid.

Effect of Oral Misoprostol After Second-Trimester Delivery

In Brief OBJECTIVE To determine whether serial oral misoprostol shortens the third stage of labor in second-trimester pregnancy loss. METHODS This was a randomized, double-blind, placebo-controlled study of women between 13 and 28 weeks' gestation admitted for spontaneous or induced pregnancy termination. Subjects were randomized to receive either misoprostol (200 μg) or placebo orally every hour for a maximum of three doses if the placenta had not delivered spontaneously within 10 minutes of the fetus. A dilute oxytocin infusion was given to women in both groups. The patients were managed expectantly until intervention was required or up to 6 hours when curettage was scheduled. RESULTS One hundred eighteen women were randomized to misoprostol and 119 randomized to placebo. Fifty-eight (49%) and 55 (46%) of the misoprostol and placebo groups, respectively, did not receive their medication (P = .65, χ2 test). There was no difference between the groups with regard to demographic features, method of pregnancy termination, or gestational age. Sixty-seven (57%) and 62 (52%) of the misoprostol and placebo groups, respectively, completed the third stage of labor within 2 hours (P = .47, χ2 test). There was no statistically significant difference in the median time from fetus to placenta (60 versus 91 minutes in the misoprostol versus placebo group, P = .57, Mann-Whitney U test). There was no difference between the groups in the incidence of hemorrhage, need for transfusion, or curettage rate. CONCLUSION The therapeutic use of oral misoprostol in the third stage of labor in second-trimester pregnancy loss does not reduce the time to complete spontaneous placental delivery. Oral misoprotol does not shorten the third stage of labor in second-trimester deliveries.

Effect of oral misoprostol after second-trimester delivery: a randomized, blinded study

OBJECTIVE:To determine whether serial oral misoprostol shortens the third stage of labor in second-trimester pregnancy loss.METHODS:This was a randomized, double-blind, placebo-controlled study of women between 13 and 28 weeks’ gestation admitted for spontaneous or induced pregnancy termination. Subjects were randomized to receive either misoprostol (200 μg) or placebo orally every hour for a maximum of three doses if the placenta had not delivered spontaneously within 10 minutes of the fetus. A dilute oxytocin infusion was given to women in both groups. The patients were managed expectantly until intervention was required or up to 6 hours when curettage was scheduled.RESULTS:One hundred eighteen women were randomized to misoprostol and 119 randomized to placebo. Fifty-eight (49%) and 55 (46%) of the misoprostol and placebo groups, respectively, did not receive their medication (P = .65, χ2 test). There was no difference between the groups with regard to demographic features, method of pregnancy termination, or gestational age. Sixty-seven (57%) and 62 (52%) of the misoprostol and placebo groups, respectively, completed the third stage of labor within 2 hours (P = .47, χ2 test). There was no statistically significant difference in the median time from fetus to placenta (60 versus 91 minutes in the misoprostol versus placebo group, P = .57, Mann-Whitney U test). There was no difference between the groups in the incidence of hemorrhage, need for transfusion, or curettage rate.CONCLUSION:The therapeutic use of oral misoprostol in the third stage of labor in second-trimester pregnancy loss does not reduce the time to complete spontaneous placental delivery.

Epidural analgesia does not prolong the third stage of labour.

To investigate whether there is an association between epidural analgesia and duration of third stage of labour, and between epidural analgesia and type of placental delivery (spontaneous vs expressed vs manual). We examined, retrospectively, the computerized labour and delivery data of all 7,468 parturients who had vaginal deliveries from 1996 to 1999 at the Civic Campus of the Ottawa Hospital. There was no difference in duration of third stage of labour between women with and without epidural pain relief who had spontaneous or expressed (fundal pressure/gentle cord traction) placental delivery. Duration of third stage of labour was shorter in women with epidural analgesia requiring manual removal of placenta. (25.3 min vs 40.1 min, P < 0.0001). The incidence of expressed placental delivery or manual removal of placenta was not different between the groups. We conclude that there is no clinically important difference in duration of third stage of labour between women with or without epidural analgesia who have spontaneous placental delivery or placental expulsion with fundal pressure/gentle cord traction. However, duration of third stage of labour was shorter in women who received epidural analgesia and required manual removal of the placenta.

Does Uterine Wiping Influence the Rate of Post-Cesarean Endometritis?

One of the traditional obstetrical practices not yet subject to prospective studies is to wipe the uterine cavity with a laparotomy pad after fetal and placental delivery to remove any remaining fetal membranes and placental fragments. This study compared two methods of achieving this at the time of cesarean delivery: uterine wiping (by hand, using a dry laparotomy pad) and tissue forceps. All 614 women in the uterine wipe group and 616 in the no-wipe group were uninfected at the time of nonemergency cesarean delivery. The two groups were demographically similar. All parturients received an intravenous bolus of 1 g of a first-generation cephalosporin immediately after the cord was clamped. Postpartum endometritis was diagnosed when the body temperature was 100.4°F or higher on two occasions 6 hours apart (excluding the first 24 hours) and there was uterine tenderness and/or foul-smelling lochia. Postpartum endometritis was diagnosed in 65 women having manual uterine wiping and in 66 in the no-wipe group, for respective incidence rates of 10.5% and 10.7%. None of 10 patients who received prophylaxis against subacute bacterial endocarditis developed infection. Numerous intrapartum factors including gestational age, type of anesthesia, duration of amnion rupture, method of placental removal, and total operating time did not differ significantly in the two study groups. Neonatal outcomes also were similar with respect to birth weight, umbilical artery pH, and admission to newborn intensive care. Although it may seem reasonable that removing residual membrane and placental tissue after cesarean delivery would help prevent endometritis, how this is done does not seem to be important. Manual wiping with a pad and the use of tissue forceps were comparably effective in this series.

Placental Regulation of Fatty Acid Delivery and its Effect on Fetal Growth—A Review

More than 90 per cent of the fat deposition in the fetus occurs in the last 10 weeks of pregnancy during which it increases exponentially to reach a rate of accretion of around 7g/day close to term. All of the n -3 andn -6 fatty acid structure acquired by the fetus has to cross the placenta and fetal blood is enriched in long chain polyunsaturated fatty acids (LCPUFA) relative to the maternal supply. The placenta may regulate its own fatty acid substrate supply via the action of placental leptin on maternal adipose tissue. Fatty acids cross the microvillous and basal membranes by simple diffusion and via the action of membrane bound and cytosolic fatty acid binding proteins (FABPs). The direction and magnitude of fatty acid flux is mainly dictated by the relative abundance of available binding sites. The fatty acid mix delivered to the fetus is largely determined by the fatty acid composition of the maternal blood although the placenta is able to preferentially transfer the important PUFA to the fetus as a result of selective uptake by the syncytiotrophoblast, intracellular metabolic channelling of individual fatty acids, and selective export to the fetal circulation. Placental FABP polymorphisms may affect these processes. There is little evidence to suggest that placental delivery of fatty acids limits normal fetal growth although the importance of the in utero supply may be to support post-natal development as most of the LCPUFA accumulated by the fetus is stored in the adipose tissue for use in early post-natal life.

Korrelation zwischen sonographischen und klinischen Befunden in der Plazentarperiode - Lösungszeiten, Lösungszeichen und Lösungsmodus

Objective: We analyzed the duration and phases of the third stage of labor with gray-scale and color Doppler sonography. We also compared ultrasound findings with the clinical signs of placental separation and the mode of placental delivery. Methods: The third stage of labor was recorded by color Doppler sonography in 57 patients after vaginal delivery. Results: The third stage of labor can be broken down into three distinct phases. The latent phase consists of the interval between delivery of the newborn and beginning placental separation (median duration 141 sec, range 5 - 790 sec). The beginning of this phase was marked by cessation of blood flow between the myometrium and the placenta. The detachment phase is characterized by shearing off of the placenta from the myometrium (median duration 50 sec, range 15-100 sec). The expulsion phase begins with completed separation and ends with the vaginal delivery of the placenta (median 80.5 sec, range 2-385 sec). Kustner's sign (absent umbilical cord retraction on suprapubic pressure) was positive and Schroder's sign (fundal elevation) in 98% of women with sonographically separated placentae. Clinically, placental separation by the Schultze mechanism was present in 45 cases (79%). In contrast, sonography showed that placental separation began from the inferior pole of the placenta without retroplacental hematoma in all cases. Conclusion: The third stage of labor consists of three distinct phases. The duration of the third stage is determined mainly by the latent phase, in which blood flow between the myometrium and the placenta ceases. Clinical and sonographic signs of placental separation correlate closely. The lower part of the placenta usually separates first, so that the mechanism described by Schultze is only of theoretical interest.