Ingemar Ingemarsson

Gender aspects of preterm birth

It was previously believed that sex differentiation took place when the undifferentiated gonads formed either testes or ovaries. Studies in recent years indicate that sex differentiation begins at conception. The SRY gene on the Y‐chromosome is already transcribed at the 2‐cell stage and triggers growth acceleration in the XY embryos. This accelerated growth is believed to be important for the male embryo as it allows complete testicular differentiation before the levels of oestrogenic hormones become too high as pregnancy progresses. It is well known that the death rate is higher for male than for female fetuses and that the increase is about 30% in chromosomally normal spontaneous abortions (i.e. significantly higher than at birth). National figures from Sweden show that boys are more likely to be delivered prematurely, accounting for 55–60% of all newborns between 23 and 32 gestational weeks. Neonatal deaths in these gestational weeks are also more common among boys. In 1993, the overall 1‐year mortality rate (including all gestational weeks) in Sweden was 5.4% for boys and 4.1% for girls. The difference in infant mortality (within 1 year) is most pronounced at extremely early birth (23–24 gestational weeks) being 60% for boys compared with 38% for girls. The release of catecholamines during labour is an important defence mechanism by a hypoxic fetus. Preterm females have significantly higher catecholamine levels than males, which may explain the better outcome in females after a hypoxic event. Deaths occurring secondary to respiratory distress syndrome are greater for males and their cognitive recovery from perinatal intracranial haemorrhage is worse. Pulmonary hypoplasia after preterm rupture of the membranes is significantly more common among male newborns.Gender differences in mode of delivery, fetal heart rate in labour, acidaemia at birth, and age degenerative changes will also be discussed.

Glomerular endotheliosis in normal pregnancy and pre‐eclampsia

Objective To investigate the proportion of women with findings characteristic for pre‐eclampsia, as opposed to renal disease, in a controlled study of hypertensive pregnant women undergoing antepartum renal biopsy.

Stillbirths and rate of neonatal deaths in 76,761 postterm pregnancies in Sweden, 1982-1991: a register study

Objective. To study stillbirths and neonatal mortality in the postterm period.Stillbirths and rate of neonatal deaths in 76,761 postterm pregnancies in Sweden, 1982-1991

Routine measurements of umbilical artery lactate levels the prediction of perinatal outcome

OBJECTIVE Our purpose was to compare lactate levels with acid-base balance in the umbilical artery with respect to the prediction of pregnancy outcome. STUDY DESIGN A prospective study of 4045 cord samples was performed. Lactate was measured with a new method that requires 5 microliters of blood and provides the result within 1 minute. RESULTS The umbilical artery lactate concentrations were significantly elevated in instrumental deliveries (2.65 +/- 1.2 mmol/L) and in emergency cesarean sections (2.44 +/- 1.7 mmol/L) compared with spontaneous vaginal delivery (1.87 +/- 0.94 mmol/L) (p < 0.001, p < 0.001). Lactate correlated significantly to fetal pH, hemoglobin, base deficit, PCO2, and HCO3-. Lactate was comparable to pH and base deficit in sensitivity, specificity, and positive and negative predictive values in relation to morbidity and mortality. CONCLUSION Umbilical artery lactate concentration and acid-base balance predicted perinatal outcomes with similar efficacies; however, its simplicity makes lactate analysis an interesting alternative in obstetric care.

Preeclampsia is associated with a reduced response to activated protein C

OBJECTIVE Resistance to activated protein C is an inherited mutation of the coagulation factor V gene, a major factor predisposing to thromboembolic events. The purpose of this study was to investigate the occurrence of heterozygote and homozygote activated protein C resistance in women with preeclampsia. STUDY DESIGN Activated protein C resistance and protein C and antithrombin III levels were determined in women (n = 50) with a history of preeclampsia and in controls (50 women with a previous normal pregnancy). The mutation of the factor V gene was analyzed. RESULTS Activated protein C resistance was found in 22% of women with previous preeclampsia compared with 10% among controls. Two women in the previous preeclampsia group had a homozygote mutation of factor V; the others were heterozygous. There was a significant difference in the activated protein C ratio between women with previous preeclampsia and the control group, 2.6 +/- 0.4 versus 3.1 +/- 0.5 (p = 0.04). None of the women had protein C or antithrombin III deficiency. CONCLUSION The results indicate that activated protein C resistance may be a contributory factor in the pathogenesis of preeclampsia.

Risk factors for fever in labor

Objective To identify risk factors for fever in labor. Methods A retrospective case-control study was conducted. Maternal sublingual temperature was measured every 2–4 hours during labor in 3109 of 3860 consecutive term parturients presenting from September 1992 through December 1993. Women who had fever (at least one recorded temperature of 38C or more, n = 72) during labor were compared with those who remained afebrile (n = 3037). Furthermore, a matched-pair case-control study was conducted, involving 250 women at term who developed fever in labor and 250 controls matched for parity and duration of labor; all delivered between January 1989 and December 1993. A conditional multiple logistic regression analysis was used to identify independent risk factors for fever during labor. Results In the case-control study, fever was associated with epidural analgesia, nulliparity, and a long duration of labor. These three variables were also related among themselves. However, multiple regression analysis showed that all three variables were independently associated with maternal temperature. In the matched-pair study, epidural analgesia, rupture of membranes longer than 24 hours, latency phase exceeding 8 hours, and a temperature in the upper normal range (37.5–37.9C) at admission were independent risk factors for developing fever in labor. Conclusion Epidural analgesia, duration of labor, and a long interval from rupture of membranes to delivery were independent risk factors for maternal fever in labor.

LONG-TERM FOLLOW-UP OF PRETERM INFANTS IN BREECH PRESENTATION DELIVERED BY CÆSAREAN SECTION: A Prospective Study

All forty-two breech infants delivered by caesarean section before the 37th gestational week since Jan. 1, 1975, were followed up prospectively. Outcome in this group was compared with that for all forty-eight breech infants delivered vaginally in 1971-74, before the introduction of routine caesarean section. Delivery by caesarean section significantly reduced the frequency of severe prolonged asphyxia, and neonatal mortality was reduced from 14.6% to 4.8%. At 12 months of age 24% of those delivered vaginally had developmental or neurological abnormalities compared with 2.5% of those delivered by caesarean section.

Serum cystatin C reflects glomerular endotheliosis in normal, hypertensive and pre‐eclamptic pregnancies

Objective To study the correlation between serum cystatin C levels and renal structural changes in normal, hypertensive and pre‐eclamptic pregnancy to evaluate it as a marker of the degree of renal involvement in pre‐eclampsia.

Urodynamic studies in normal pregnancy andin puerperium

Fourteen primiparas (11 pregnant for the first time, and three with a history of one abortion) were examined during pregnancy to elucidate changes in parameters of importance of maintenance of urinary continence. Urethral pressure profile measurements and simultaneous urethrocystometry were carried out in the beginning of pregnancy (weeks 12 to 16), in the thirty-eighth week, and 5 to 7 days after delivery. Both the absolute and functional lengths of the urethra were found to increase throughout pregnancy by median values of 6.7 and 4.8 mm, respectively. Also, the maximum urethral pressure increased gradually during pregnancy, returning within 1 week after delivery to almost the same value as at the beginning of pregnancy. The urethral closure pressure also increased throughout pregnancy. Thus, the results of the investigation revealed that the physiologic changes which took place within the urethra during pregnancy were to advantage from standpoint of maintaining continence.

Randomised controlled trial of atenolol and pindolol in human pregnancy: effects on fetal haemodynamics.

OBJECTIVE--To compare the effects of uteroplacental circulation of two beta adrenoceptor blockers, atenolol (cardioselective) and pindolol (non-selective with intrinsic sympathomimetic activity). DESIGN--Controlled double blind double dummy study. SETTING--Departments of obstetrics and gynaecology in two Swedish university hospitals. SUBJECTS--29 women with pregnancy induced hypertension in the third trimester, 13 randomised to atenolol and 16 to pindolol. MAIN OUTCOME MEASURES--Pulsatility index in fetal aorta, umbilical artery, and maternal arcuate artery. Volumetric blood flow in fetal aorta and umbilical vein. RESULTS--Mean arterial blood pressure decreased by 9.0 (95% confidence interval -13.0 to -5.0) mm Hg in the atenolol group and by 7.8 (-11.4 to -4.2) mm Hg in the pindolol group. During atenolol treatment the pulsatility index increased significantly from 1.82 (SD 0.20) to 2.07 (0.32) in the fetal thoracic descending aorta, from 1.44 (0.28) to 1.79 (0.27) in the abdominal aorta, and from 0.93 (0.17) to 1.05 (0.19) in the umbilical artery; the volumetric blood flow in the umbilical vein decreased from 106 (28.8) to 84 (22.6) ml/min/kg. No such changes were seen after treatment with pindolol. Birth weight was similar in the two groups but placental weight was significantly different (529 (122) g in atenolol group v 653 (136) g in pindolol group; p = 0.03). CONCLUSION--The hypotensive effect was similar with both drugs, but only the beta 1 blocker atenolol had significant effects on fetal haemodynamics, although within normal ranges. The implications of these findings can be only speculative, but negative fetal consequences of beta 1 adrenoceptor blockade cannot be excluded.