Effect of labour induction on rates of stillbirth and cesarean section in post-term pregnancies. (1/67)

BACKGROUND: Meta-analyses of randomized controlled trials suggest that elective induction of labour at 41 weeks' gestation, compared with expectant management with selective labour induction, is associated with fewer perinatal deaths and no increase in the cesarean section rate. The authors studied the changes over time in the rates of labour induction in post-term pregnancies in Canada and examined the effects on the rates of stillbirth and cesarean section. METHODS: Changes in the proportion of total births at 41 weeks' and at 42 or more weeks' gestation, and in the rate of stillbirths at 41 or more weeks' (versus 40 weeks') gestation in Canada between 1980 and 1995 were determined using data from Statistics Canada. Changes in the rates of labour induction and cesarean section were determined using data from hospital and provincial sources. RESULTS: There was a marked increase in the proportion of births at 41 weeks' gestation (from 11.9% in 1980 to 16.3% in 1995) and a marked decrease in the proportion at 42 or more weeks (from 7.1% in 1980 to 2.9% in 1995). The rate of stillbirths among deliveries at 41 or more weeks' gestation decreased significantly, from 2.8 per 1000 total births in 1980 to 0.9 per 1000 total births in 1995 (p < 0.001). The stillbirth rate also decreased significantly among births at 40 weeks' gestation, from 1.8 per 1000 total births in 1980 to 1.1 per 1000 total births in 1995 (p < 0.001). The magnitude of the decrease in the stillbirth rate at 41 or more weeks' gestation was greater than that at 40 weeks' gestation (p < 0.001). All hospital and provincial sources of data indicated that the rate of labour induction increased significantly between 1980 and 1995 among women delivering at 41 or more weeks' gestation. The associated changes in rates of cesarean section were variable. INTERPRETATION: Between 1980 and 1995 clinical practice for the management of post-term pregnancy changed in Canada. The increased rate of labour induction at 41 or more weeks' gestation may have contributed to the decreased stillbirth rate but it had no convincing influence either way on the cesarean section rate.  (+info)

The effect of indomethacin on uterine contractility and luteal regression in pregnant rats at term. (2/67)

Treatment of pregnant rats with 1 mg indomethacin/kg twice daily i.m. beginning on Day 20 delayed the onset of parturition by about 21 hr and prolonged the duration of spontaneous parturition by 4 hr. Plasma progesterone and oestradiol levels were determined in daily samples of peripheral blood, and uterine contractions were recorded before and during parturition by means of small, chronically implanted intrauterine balloons which were connected to pressure transducers via fluid-filled catheters. Indomethacin treatment did not inhibit or suppress spontaneous or oxytocin-induced contractions, which were of the same intensity in indomethacin-treated as in control rats. Parturition was induced with oxytocin in the same proportion of treated and control rats, but its induction was not successful in treated rats until 1 day later than in control rats, but its induction was not successful in treated rats until 1 day later than in controls. The onset of parturition was always related to the plasma progesterone level, which declined at a slower rate in indomethacin-treated than in control rats, reaching baseline values approximately 1 day later in the treated animals. The appearance of 20alpha-hydroxysteroid dehydrogenase in the CL of pregnant rats normally occurs on Day 21 of gestation, but activity was not observed until about 1 (0-3) day later in the indomethacin-treated rats, indicating that luteolysis was retarded. Prostaglandin F-2alpha infusions given on Day 21 reversed the effects of indomethacin treatment on plasma progesterone, luteal 20alpha-hydroxysteroid dehydrogenase activity and the timing and duration of parturition, and reduced the high perinatal mortality associated with indomethacin treatment, suggesting that the effects of indomethacin were related to its inhibitory action on prostaglandin synthetase activity. It is concluded that, in rats, indomethacin exerts its effects on parturition through inhibition of luteal regression which was significantly retarded but not prevented, and that indomethacin does not have a direct effect on myometrial contractility.  (+info)

Recurrence of prolonged pregnancy. (3/67)

BACKGROUND: We conducted a cohort study in an attempt to determine whether prolonged pregnancy in mother is a risk factor for prolonged pregnancy in daughter, and if previous prolonged pregnancy is a risk factor for prolonged pregnancy in subsequent pregnancy. METHODS: Data from the Swedish Medical Birth Registry were combined with a local registry of births (1955-1990). Mother-daughter pairs (with events of delivery in each generation) were identified. Relative risk (RR) and its 95% confidence interval (CI) were calculated and population attributable proportion was estimated when appropriate. RESULTS: If mother had had prolonged pregnancy at delivery of daughter the relative risk (RR) of prolonged pregnancy in daughter was moderately raised (RR = 1.3; CI : 1.0-1.7) with population attributable proportions ranging between 2.1% and 4.6%. If previous pregnancy had been prolonged, the RR of prolonged pregnancy at subsequent birth was increased 2-3 fold with population attributable proportions of 12.5% to 15.8%. Possible confounders such as mother's parity, age and maternal age did not alter the risks. CONCLUSIONS: Although moderate, prolonged pregnancy in mother may be a risk factor for prolonged pregnancy in daughter. A previous prolonged pregnancy increases the risk of prolonged pregnancy in a subsequent birth. However, the familial factor of prolonged pregnancy explains just a minor part of its occurrence in the population (due to small population attributable proportions).  (+info)

Fetal outcome in pregnancies defined as post-term according to the last menstrual period estimate, but not according to the ultrasound estimate. (4/67)

OBJECTIVE: To study the risk of adverse fetal outcome in fetuses that were post-term according to the last menstrual period estimate but not according to the ultrasound estimate. DESIGN: A total of 11,510 women with singleton pregnancies, reliable last menstrual period and delivery after 37 weeks were divided into four groups: women who delivered at term, i.e. within 259-295 days according to both the ultrasound and the last menstrual period estimate; women who delivered post-term according to the last menstrual period estimate but not according to the ultrasound estimate; women who delivered post-term according to the ultrasound estimate but not according to the last menstrual period estimate; and women who delivered post-term according to both the ultrasound and the last menstrual period estimates. Stepwise logistic regression was used to test whether the risk of Apgar score of < 7 after 5 min and transfer to the neonatal intensive care unit increased in any of the post-term groups. RESULTS: There was no significant difference in mortality between the term group and the three study groups. There was no significant increase in the risk for Apgar score of < 7 after 5 min or transfer to the neonatal intensive care unit for pregnancies that were defined as post-term according to the last menstrual period estimate but not according to the ultrasound estimate. There was, however, an increased risk for Apgar score of < 7 after 5 min in the group that was post-term according to the ultrasound estimate but not according to the last menstrual period estimate. There was also an increased risk for transfer to the neonatal intensive care unit in the group that was post-term according to both estimates. CONCLUSION: The effect of ultrasound in changing the estimated day of delivery to a later date leading to pregnancies becoming post-term according to the last menstrual period estimate but not according to the ultrasound estimate does not have any adverse consequences for the fetal outcome. However, there seems to be an increased risk for adverse consequences for pregnancies that are post-term according to the ultrasound estimate.  (+info)

Isoenzymes of N-acetyl-beta-hexosaminidase in complicated pregnancy. (5/67)

The activity of N-acetyl-beta-hexosaminidase was found to be significantly higher in the placentas collected after delivery from women in puerperium with symptoms of prolonged pregnancy or complicated by EPH gestosis, than in placentas from normal pregnancy. Isoelectrofocusing of placenta homogenates showed the presence of isoenzymes A, P and B of N-acetyl-beta-hexosaminidase. Different isoenzyme A patterns in homogenates were observed in placentas obtained from normal and prolonged pregnancies and in those complicated by EPH gestosis.  (+info)

Fetal arterial and venous Doppler parameters in the interpretation of oligohydramnios in postterm pregnancies. (6/67)

OBJECTIVE: The objective of the current study was to evaluate fetal arterial and venous Doppler parameters in postterm pregnancies with oligohydramnios and those with normal amniotic fluid. STUDY DESIGN: A cross-sectional study was performed in 38 pregnancies beyond 41 weeks' gestation. Pulsed Doppler imaging was used to determine the pulsatility index (PI) for the fetal middle cerebral artery (MCA), renal artery, umbilical artery, inferior vena cava (IVC) and ductus venosus. The amniotic fluid index (AFI) was used for semiquantitive assessment of amniotic fluid volume. Oligohydramnios was defined as an AFI < 5 cm. RESULTS: Oligohydramnios was detected in 10 cases, and a normal AFI was present in 28 cases. In the presence of oligohydramnios the PI of the MCA was decreased, while the renal artery PI and the MCA PI/UA PI ratio were found to be elevated. In cases of oligohydramnios the PI in the IVC was increased but was unchanged in the ductus venosus. CONCLUSION: Oligohydramnios in post-term pregnancies is associated with arterial redistribution of fetal blood flow typifying the brain sparing effect and with decreased resistance in the MCA and increased resistance in the fetal IVC.  (+info)

Non-reassuring fetal status in the prolonged pregnancy: the impact of fetal weight. (7/67)

OBJECTIVE: To evaluate the incidence of abnormal fetal findings and Cesarean delivery for non-reassuring fetal status as a function of birth weight in the uncomplicated prolonged pregnancy. METHODS: Seven hundred and ninety-two patients at or beyond 41 weeks' gestation were managed expectantly. Population-specific birth-weight percentiles were calculated. Fetuses were retrospectively categorized as small (birth weight < 10th percentile), average (10th percentile < or = birth weight < or = 90th percentile) or large (birth weight > 90th percentile). The incidences of abnormal antepartum fetal testing results (i.e. oligohydramnios and/or abnormal non-stress testing) and Cesarean delivery for intrapartum non-reassuring fetal status were calculated for these three birth-weight categories. RESULTS: There was a significant inverse relationship between the incidence of abnormal fetal testing and birth-weight category (36%, 14% and 9% for small, average and large fetuses, respectively, P < 0.001). Small fetuses were more likely to require a Cesarean delivery for non-reassuring fetal status during labor than were all other fetuses (12.3% vs. 5.3%, P = 0.024). CONCLUSIONS: The frequency of oligohydramnios and abnormal non-stress testing is inversely related to birth weight in the expectantly managed prolonged pregnancy. In addition, small fetuses born at or beyond 41 weeks' gestation have an increased rate of Cesarean delivery for intrapartum non-reassuring fetal status.  (+info)

Comparative accuracy of clinical estimate versus menstrual gestational age in computerized birth certificates. (8/67)

OBJECTIVE: This study compares gestational age data obtained by clinical estimate with data calculated from the date of the last menstrual period (LMP) as recorded on birth certificates. METHODS: The authors analyzed 476,034 computerized birth records from three overlap years, that is, those that contained both menstrual and clinical estimates of gestational age, concentrating on cases within the biologically plausible range of 20-44 weeks. RESULTS: The overall exact concordance between the two measurements was 46%. For +1 week it was 78%, and for +2 weeks it was 87%. Incidence of prematurity was 16% with menstrual gestational age, while it was 12% with clinical estimate. About 47% of the LMP-based preterm births were classified as term by clinical estimate. Eighty-three percent of clinical estimate-based preterms were also preterms by LMP-based gestation. Birthweight frequency distribution curves for LMP-based gestational age are bimodal, indicating probable miscoding of term births. An apparent over-representation of births coded as exactly 40 weeks by clinical estimate suggests rounding off near term for this method. CONCLUSION: Agreement between menstrual and clinical estimates of gestational age occurs most often close to term, with significant disagreement in preterm and postterm births. Use of different methods of determining gestation in different years or geographic populations will result in artifactual differences in important indicators such as prematurity rate.  (+info)