Maternal exercise, season and sex modify the daily fetal heart rate rhythm

AIM

The knowledge on biological rhythms is rapidly expanding. We aimed to define the longitudinal development of the daily (24-hour) fetal heart rate rhythm in an unrestricted, out-of-hospital setting and to examine the effects of maternal physical activity, season and fetal sex.

METHODS

We recruited 48 women with low-risk singleton pregnancies. Using a portable monitor for continuous fetal electrocardiography, fetal heart rate recordings were obtained around gestational weeks 24, 28, 32 and 36. Daily rhythms in fetal heart rate and fetal heart rate variation were detected by cosinor analysis; developmental trends were calculated by population-mean cosinor and multilevel analysis.

RESULTS

For the fetal heart rate and fetal heart rate variation, a significant daily rhythm was present in 122/123 (99.2%) and 116/121 (95.9%) of the individual recordings respectively. The rhythms were best described by combining cosine waves with periods of 24 and 8 hours. With increasing gestational age, the magnitude of the fetal heart rate rhythm increased, and the peak of the fetal heart rate variation rhythm shifted from a mean of 14:25 (24 weeks) to 20:52 (36 weeks). With advancing gestation, the rhythm-adjusted mean value of the fetal heart rate decreased linearly in females (P < .001) and nonlinearly in males (quadratic function, P = .001). At 32 and 36 weeks, interindividual rhythm diversity was found in male fetuses during higher maternal physical activity and during the summer season.

CONCLUSION

The dynamic development of the daily fetal heart rate rhythm during the second half of pregnancy is modified by fetal sex, maternal physical activity and season.

Women with a history of placental abruption: when in a subsequent pregnancy should special surveillance for a recurrent placental abruption be initiated?

BACKGROUND

It is common to admit to hospital or start intensive ambulatory antenatal care of pregnant women with a previous placental abruption using the gestational age of the previous placental abruption as a starting point. In some instances, close surveillance may be commenced much earlier. There is no consensus when in a subsequent pregnancy such measures should be initiated.

OBJECTIVE

The analyses aimed at the prevention of complicated (preterm, small for gestational age, or perinatal death) recurrent placental abruptions, assessing at which time in a subsequent pregnancy special surveillance should start in order to anticipate and prevent a recurrence.

DESIGN

A cohort study based on the Medical Birth Registry of Norway. Calculation of gestational age specific risks of placental abruption in a second pregnancy and estimation of when to initiate surveillance in order to reduce an increased risk of recurrent placental abruption to the initial level of initial abruption in the second pregnancy.

RESULTS

In women with a complicated (preterm, small for gestational age, or perinatal death) first delivery, the risks of an initial and recurrent complicated placental abruption in the second pregnancy were 7/1000 and 33/1000, respectively (relative risk 4.9). To reduce the recurrence risk in a second pregnancy to 7/1000, special surveillance six weeks prior to the gestational age of the initial abruption would be necessary. In women with an uncomplicated first delivery, the risks in the second pregnancy of an initial and recurrent complicated abruption were 3 and 19/1000, respectively (relative risk 7.1). To reduce the recurrence risk to 3/1000, surveillance at least 12 weeks prior would be necessary.

CONCLUSION

The increased recurrence rate would necessitate increased awareness in terms of special surveillance in the second pregnancy. In pregnancies at risk of a recurrent placental abruption, monitoring up to three months before the gestational age of the initial abruption is necessary.

Peripartum hysterectomy-incidence and maternal morbidity

BACKGROUND

The aim of the study was to find the incidence and clinical implications of peripartum hysterectomy in our department and to identify women at risk to improve treatment before resorting to hysterectomy.

MATERIAL AND METHODS

In the period 1981-1996, cases with peripartum hysterectomy among a total of 70,546 deliveries in our department were identified from three different sources. The clinical variables were obtained by review of the maternal records.

RESULTS

In the study period, 11 cases, representing an incidence of 0.2 peripartum hysterectomies per 1000 deliveries was found. Eight women had a cesarean section and three women had a spontaneous vaginal delivery. Six of the patients had previous operation on the uterus. The indication for hysterectomy was atony in seven, suspected rupture in two, placenta accreta in one and DIC in one woman. The maternal morbidity was substantial as the mean number of transfusions given was 15 units (range 7-24), and the mean hospitalization time was 15 days (range 11-29). There was no maternal mortality, but one infant died due to asphyxia caused by placental abruption.

CONCLUSIONS

The incidence of peripartum hysterectomy was low, but the condition is serious with significant maternal morbidity.

Predicting preeclampsia in the second pregnancy from low birth weight in the first pregnancy

OBJECTIVE

To evaluate the effect of low birth weight adjusted for gestational age in first pregnancies on preeclampsia in second pregnancies and to estimate the proportion of preeclampsia in second pregnancies attributable to histories of LBW for gestational age.

METHODS

We conducted a cohort study based on linked data from the Medical Birth Registry of Norway, which covered all births in 1967-1992.

RESULTS

Women who delivered infants under the third percentile birth weight were three times more likely to have initial or recurrent preeclampsia in second pregnancies than those who delivered infants at or above the tenth percentile. After adjusting for maternal age, year of birth, interpregnancy interval, education, chronic hypertension, diabetes mellitus, and change of partner, the increased risk persisted. Birth weight below the tenth percentile in the first delivery accounted for 10% of the total cases of preeclampsia in the second pregnancy and 30% of recurrent cases.

CONCLUSION

A history of low birth weight adjusted for gestational age is associated significantly with subsequent occurrence as well as recurrence of preeclampsia. These findings are consistent with the hypothesis of a shared etiologic factor or recurrent pathophysiologic mechanism for preeclampsia and fetal growth restriction. A history of fetal smallness for gestational age is found in a substantial proportion of all cases of preeclampsia and thus seems to be important in the etiology of preeclampsia.

Obstetric history and the risk of placenta previa

OBJECTIVE

To evaluate secular trends in the occurrence of placenta previa and whether placenta previa is associated with the outcome of previous pregnancies, cesarean section, and sociodemographic factors.

DESIGN

A cohort study based on the Medical Birth Registry of Norway. Placenta previa in the second pregnancy was investigated for associations with outcomes in the first pregnancy and sociodemographic factors.

RESULTS

In birth orders 1 and 2 the occurrence of placenta previa was 1.2 and 2.2 per 1,000, respectively, with no secular trend. The occurrence increased with maternal age and was lowest in women aged 20-29 years. The recurrence rate was 23 per 1,000 (adjusted odds ratio (OR) of recurrence=9.7). In women with prior delivery at < or =25 gestational weeks the risk of placenta previa was 6.7 per 1,000 (adjusted OR=3.0). In women with prior placental abruption the risk was 5.8 per 1,000 (OR=2.6). In women with prior perinatal death the risk was 4.4 per 1,000 (adjusted OR= 1.8). No independent relationship emerged with socio-economic factors, previous birthweight, and a history of pregnancy induced hypertension. Cesarean section was associated with subsequent development of placenta previa (adjusted OR= 1.3).

CONCLUSIONS

We found no secular trends in the occurrence of placenta previa. Placenta previa is associated with previously described risk factors for placental abruption. The increased risk of placenta previa subsequent to placental abruption supports the theory of a shared etiologic factor. However, placenta previa and placental abruption do not share a common etiology in relation to a history of pregnancy induced hypertension, fetal growth retardation, and socio-economic factors.

Secular trends in peri- and neonatal mortality in breech presentation; Norway 1967-1994

OBJECTIVES

To assess secular trends in mortality rates in breech presentation in Norway and the effects of gestational age, birth defects and delivery method.

MATERIAL AND METHODS

The Medical Birth Registry of Norway 1967-1994, with 45,579 breech presentation births from 24 weeks of gestation onwards, with mortality rate comprising all stillbirths from 24 completed weeks of gestation and all neonatal deaths (extended peri- and neonatal mortality) as main outcome variable.

RESULTS

The extended peri- and neonatal mortality rate in breech presentation births declined during the study period from 9.2% in 1967-76 to 5.5% in 1977-86 and to 3.0% in 1987-94. The highest relative risk of mortality in breech presentation versus the total birth population was observed in intrapartum death and in mortality less than 24 hours after delivery. Stillbirth represented about half of the extended peri- and neonatal mortality throughout the study period. Also in infants with birth defects, the survival increased during the study period. The extended peri- and neonatal mortality was highest in vaginal deliveries, but decreased during the period, irrespective of delivery method.

CONCLUSIONS

Probably due to improved obstetrical and neonatal care, mortality associated with breech presentation has substantially decreased. Increased focus especially on stillbirth, might be instrumental in further reducing the mortality associated with breech presentation.

Manual removal of the placenta. Incidence and clinical significance

OBJECTIVE

To determine the incidence and complications related to manual removal of the placenta.

METHODS

Review of hospital medical records from 1990 throughout 1994. One thousand five hundred and two vaginal deliveries from 1984 1992 were used for comparisons.

RESULTS

A total of 24,750 deliveries were registered during the five year study period. Placenta was removed manually in 165 women (0.6%). The use of general anesthesia for manual removal of placenta decreased from 74% in 1990 to 19% in 1994. Spinal analgesia was applied from 1993, and it was used in 42% of the women in 1994. Of 74 parous women, 12 (16%) had experienced retained placenta before. The average difference in the hemoglobin concentration between the prenatal and the postoperative values was 3.4 g/dl among the patients, and 10% required blood transfusion (1-4 units). Among the controls, there was no decrease in the average hemoglobin concentration, and only 0.5 needed blood transfusion. Endometritis following manual removal was detected in 1.8% of the patients and 1.5% among the controls. Despite manual removal, five women (3%) were considered to have retained placental fragments two days or later after delivery, which required curettage.

CONCLUSIONS

Placenta needed to be removed manually in 0.60% of all deliveries in our department. It was associated with increased incidence of hemorrhage and consequently low hemoglobin values. Women with a history of retained placenta have an increased risk of recurrence of retained placenta in subsequent deliveries.

Perinatal mortality in breech presentation sibships

OBJECTIVE

To compare perinatal mortality in breech presentation delivered vaginally and by cesarean in individual births and in sibships.

METHODS

A national, population registry-based study, 1967-1994, was conducted, with maternal record linkage of sibships, comprising the first to the third birth of a mother. The main outcome was perinatal mortality. Odds ratios of perinatal mortality were calculated and adjusted by logistic regression analysis.

RESULTS

The overall relative perinatal mortality was 4.3 (95% confidence interval [CI] 4.1, 4.5) in breech compared with nonbreech presentation and 5.4 (95% CI 4.7, 6.2) in vaginal compared with cesarean delivery. The relative perinatal mortality in breech compared with nonbreech presentation was lowest in birth order one compared with birth orders two and three. In breech vaginal delivery compared with cesarean delivery, the opposite effect of birth order was found. The highest perinatal mortality was found in a current breech presentation of a sibship with no previous breech births. In birth subsequent to breech births, perinatal mortality was more or less independent of current presentation, without respect to delivery method. The increased perinatal mortality in breech presentation is explained partly by its association with other risk factors for perinatal death.

CONCLUSION

Women with recurring breech presentation represent a lower risk of adverse perinatal outcome. This might be explained by a biologic mechanism or by increased quality of antenatal care. An increased mortality in subsequent nonbreech siblings after a breech presentation was surprising.

Reproductive career after breech presentation: subsequent pregnancy rates, interpregnancy interval, and recurrence

OBJECTIVE

To assess subsequent pregnancy rates and recurrence of breech, as well as interpregnancy interval after a breech presentation.

METHODS

We conducted a national population registry-based study using data from 1967 to 1994, with maternal record linkage of sibships, comprising the first to the fourth birth of a mother.

RESULTS

The subsequent pregnancy rate after a surviving breech birth was lower than after a surviving nonbreech birth. Women with two births, of which one was a perinatal loss, had a higher subsequent pregnancy rate, compared with those who had surviving infants. The subsequent pregnancy rate was lower after a cesarean delivery irrespective of presentation. The interpregnancy interval was shorter if the previous infant died, whereas presentation did not influence the interval. The adjusted odds ratio of recurrence of breech increased from 4.32 (95% confidence interval [CI] 4.08, 4.59) after one previous breech delivery to 28.1 (95% CI 12.2, 64.8) after three.

CONCLUSION

Breech and cesarean delivery lowered the subsequent pregnancy rate, probably because of the women's decision not to reproduce. Thus, preconceptional counseling with information, support, and reassurance regarding future pregnancies and deliveries might reduce the discouraging effect. A high odds ratio of recurrence of breech suggests effects of recurring specific causal factors of either genetic or more permanent environmental origin.

Factors influencing delivery method in breech presentation

BACKGROUND

To study factors influencing delivery method in breech presentation.

METHODS

Population based cohort study from The Medical Birth Registry of Norway, comprising all singleton deliveries in Norway, 1967-1994, 1,592,064 deliveries of which 45,921 (2.9%) were in breech presentation.

RESULTS

The proportion of cesarean section in breech presentation increased from 3.6 per 100 in 1969 to 58.8 in 1994. The relative risk for delivery by cesarean section in breech presentation compared to the nonbreech population increased from 2.0 (95% CI 1.5-2.7) in 1967 to 5.9 (95% CI 5.6-6.2) in 1994. It declined by maternal age, increased by gestational age and was lowest among mothers with urban residence. A negative association was observed between the annual number of births at the delivery department and the cesarean section proportion. However, during the observation period, the centralization of breech deliveries to the largest departments was reduced.

CONCLUSIONS

Vaginal delivery in breech presentation was particularly observed in large delivery departments and among mothers with urban residence. Since experience and practical competence are prerequisites for successful vaginal delivery, this centralization seems justified. Further centralization of all breech presentation births should be pursued. However, preparedness as to vaginal delivery should be established also at the smaller units, e.g. by a routine providing periodical centralized training for obstetricians working in smaller institutions.

The occurrence of breech presentation in Norway 1967-1994

BACKGROUND

To study the occurrence of breech presentation and its association with demographic and geographic variables.

METHOD

Population based cohort study from the Medical Birth Registry of Norway comprising all singleton deliveries 1967-1994, a total of 1,592,064 deliveries. Of these, 45,921 in breech presentation.

RESULTS

From 1967 through 1994, the breech presentation proportion increased from 2.2% (95% CI 2.1-2.3) to 3.4% (95% CI 3.2-3.5). Breech presentation was associated with high maternal age and low birth order, as well as low gestational age and birthweight. The secular trend was mainly due to demographic changes in terms of increasing proportions of births with low birth order and high maternal age. Breech presentation was most frequent in urban areas.

CONCLUSIONS

Strong associations were observed between breech presentation and low birth order as well as high maternal age. The findings are compatible with both intrinsic as well as environmental mechanisms. A full understanding of the birth order effect necessitates further studies based on sibship data. Prevention of premature delivery would be an effective measure for reducing the breech presentation proportion.

Evaluation of a protocol for selecting fetuses in breech presentation for vaginal delivery or cesarean section

OBJECTIVE

Our purpose was to evaluate, with respect to obstetric intervention and neonatal outcome, a protocol for selecting fetuses in breech presentation for vaginal delivery or cesarean section.

STUDY DESIGN

A clinical follow-up study was performed between 1984 and 1992 of all term singleton deliveries in breech presentation. Each case selected for vaginal delivery had a matched control in vertex presentation.

RESULTS

A total of 1212 infants presented as breech. Vaginal delivery increased from 45% to 57% (p = 0.004), and cesarean section for failure of vaginal delivery declined from 21% to 6% (p < 0.00001). None, however, died or had long-term sequelae because of a complicated or failed vaginal breech delivery. A total of 8.8% of those delivered vaginally in breech versus 5.0% of those in vertex presentation were admitted to the neonatal intensive care unit (p = 0.009). Among those with vaginal delivery, 2.5% in breech presentation were given the clinical diagnosis of birth asphyxia versus none in the vertex position (p = 0.0001).

CONCLUSION

Breech presentation at term may be selected for vaginal delivery if properly managed.

[Norwegian Society of Gynecology and Obstetrics--guidelines in obstetrics. Structure, process, results and evaluation]

This paper describes structure, process, results, and evaluation of the Norwegian Society of Gynaecology and Obstetrics' Guidelines in obstetrics. This work, which lasted for 2 1/2 years, involved almost all obstetrical departments in Norway and 1/4 of all members of the Norwegian Society of Gynaecology and Obstetrics. All members of the Norwegian Society of Gynaecology and Obstetrics were invited to answer 24 questions. Of the 63% who replied to the questionnaire, 44% and 48% respectively stated that the Guidelines in obstetrics were very good or good. The introduction of the Guidelines in obstetrics led to changes in routines in more than 70% of the hospitals, and the different categories of hospital physicians changed their routines as well (55-65%). 83% of the heads of the departments stated that the Guidelines in obstetrics served partly or totally as the model for the obstetrical management guidelines. The evaluation and the experience of this quality assessment handbook serve as perspectives for future work.

Retinal detachment in association with preeclampsia and abruptio placentae

Retinal detachment is a rare complication of preeclampsia, eclampsia and abruptio placentae. We report a case of bilateral retinal detachment in association with severe preeclampsia complicated with abruptio placentae, intrauterine fetal death and disseminated intravascular coagulation. In obstetric complications, placental thromboplastin may release into maternal circulation and activate the extrinsic coagulation system with resultant disseminated intravascular coagulation. This may be responsible for choroidal ischemia and consequent serous retinal detachment.

[Breech presentation--classification and nomenclature]

In Norway the nomenclature used for the various types of breech presentation differs. In this paper the authors describe the common types of breech presentation and the nomenclature used in the Norwegian textbooks in obstetrics. Using different nomenclature can lead to misinterpretation of the different types of breech presentation which could influence the choice method of delivery. The authors propose an unambiguousness Norwegian nomenclature for the most common types of breech presentation.

Outcome of pregnancy and childbirth following laryngectomy

OBJECTS

Pregnancy and delivery in two laryngectomized women.

RESULTS

One woman had a pregnancy complicated by hypothyroidism and stenosis of the tracheostoma, she was delivered by cesarean section. The other had an uneventful pregnancy and a spontaneous vaginal delivery.

CONCLUSIONS

Individualized handling of the delivery. By modifying the technique of bearing down spontaneous vaginal delivery is possible.

Proallergens of formaldehyde applied in patch testing of formaldehyde contact allergy

The ability of the nonliquid, nonvolatile proallergen of formaldehyde, N-hydroxymethylsuccinimide, to test for contact allergy to formaldehyde has been investigated by in vitro penetration studies in human epidermis. Compared with the standard test, 1% formaldehyde in water, N-hydroxymethylsuccinimide equal to 0.8 mg formaldehyde gave a similar penetration profile. This is explained by cleavage of N-hydroxymethylsuccinimide into formaldehyde and carrier (succinimide) by transepidermal water on the surface of the skin. Results were confirmed by a guinea pig maximazation test on animals sensitized to formaldehyde and in a preliminary clinical study on nine patients with known allergy to formaldehyde.

Problems of interpreting integumental D-glucose fluxes by the integument of Schistosoma

1. The parasitic trematode Schistosoma mansoni can take up glucose across its surface at a rate three times higher than the glucose uptake by the mucosal border of the rabbit ileum. 2. Washout of tritiated polyethylene glycol (M Wt 4000) indicated that it was being lost through the integument and that the gut contribution is very small. 3. There is a peripheral diffusion resistance that will profoundly influence any transepidermal solute transfer.