FACTORS ASSOCIATED WITH BREECH DELIVERY

Cesarean delivery is not associated with decreased at-birth fracture rates in osteogenesis imperfecta

Purpose

Osteogenesis imperfecta (OI) predisposes to recurrent fractures. The moderate-to-severe forms of OI present with antenatal fractures and the mode of delivery that would be safest for the fetus is not known.

Methods

We conducted systematic analyses on the largest cohort of individuals (n=540) with OI enrolled to-date in the OI Linked Clinical Research Centers. Self-reported at-birth fracture rates were compared in individuals with OI types I, III, and IV. Multivariate analyses utilizing backward-elimination logistic regression model building were performed to assess the effect of multiple covariates including method of delivery on fracture-related outcomes.

Results

When accounting for other covariates, at-birth fracture rates did not differ based on whether delivery was by vaginal route or by cesarean section (CS). Increased birth weight conferred higher risk for fractures irrespective of the delivery method. In utero fracture, maternal history of OI, and breech presentation were strong predictors for choosing CS for delivery.

Conclusion

Our study, the largest to analyze the effect of various factors on at-birth fracture rates in OI shows that delivery by CS is not associated with decreased fracture rate. With the limitation that the fracture data were self-reported in this cohort, these results suggest that CS should be performed only for other maternal or fetal indications, but not for the sole purpose of fracture prevention in OI.

Breech presentation at delivery: a marker for congenital anomaly?

OBJECTIVE

To determine whether congenital anomalies are associated with breech presentation at the time of birth.

STUDY DESIGN

A population-based, retrospective cohort study was conducted among 460,147 women with singleton live births using the Missouri Birth Defects Registry, which includes all defects diagnosed during the first year of life. Maternal and obstetric characteristics and outcomes between breech and cephalic presentation groups were compared using χ(2)-square statistic and Student's t-test. Multivariable binary logistic regression analysis was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULT

At least one congenital anomaly was more likely present among infants breech at birth (11.7%) than in those with cephalic presentation (5.1%), whether full-term (9.4 vs 4.6%) or preterm (20.1 vs 11.6%). The relationship between breech presentation and congenital anomaly was stronger among full-term births (aOR 2.09, CI 1.96, 2.23, term vs 1.40, CI 1.26, 1.55, preterm), but not in all categories of anomalies.

CONCLUSION

Breech presentation at delivery is a marker for the presence of congenital anomaly. Infants delivered breech deserve special scrutiny for the presence of malformation.

Primitive reflexes and the determination of fetal presentation at birth

Ninety term breech-presenting singletons with birth weights greater than 2500 g and no congenital anomalies were matched with similar cephalic-presenting infants on gender and mode of delivery (n = 180). Thirteen primitive reflexes were examined at birth, 6 weeks and 3 and 5 months. No significant differences in the intensity of the asymmetrical tonic neck, symmetrical tonic neck, positive support tonic labyrinthine (prone and supine), segmental rolling (head-on-body and body-on-body), Galant, Moro, upper and lower extremity grasp, lower extremity placing and stepping reflexes were observed between these two groups of infants. Infants delivered vaginally, regardless of presentation, had weaker Moro reflexes at 5 months than infants delivered by cesarean section. The popular notion that precursors to early motor behaviors, such as the placing and stepping reflexes, are determinants of fetal presentation at the end of pregnancy is not supported by these results. Instead, spontaneously generated active whole body movements may be more significant influences of fetal orientation at the time of birth.

Mode of delivery and neonatal death in 17,587 infants presenting by the breech

OBJECTIVE

To study the effects of caesarean section on neonatal mortality in infants presenting by the breech.

DESIGN

Population-based non-experimental comparison of infants presenting by the breech born vaginally with those born by caesarean section. Neonatal mortality rates were calculated for 250 g birthweight intervals. Weight-specific relative risks (RRs) were further adjusted for birthweight in 50 g categories.

SETTING

New York City, 1978-1983. Data came from the Department of Health's computerized vital records on livebirths and infant deaths.

SUBJECTS

17,587 singleton breech livebirths greater than or equal to 500 g birthweight, with congenital anomaly deaths excluded. 6178 were born vaginally and 11409 were born by caesarean section.

MAIN OUTCOME MEASURES

Birthweight-specific and birthweight-adjusted neonatal mortality.

RESULTS

At birthweights of 501 to 1750 g, the risk of neonatal death for breech infants born vaginally was significantly higher than the risk for those born by caesarean section (weight-adjusted RR = 1.7). For breech infants with birthweights over 3000 g, the weight-adjusted risk was 5.6 times greater for a vaginal birth compared with caesarean section. The addition of 16 additional control variables in multiple logistic regression analyses did not change these RRs.

CONCLUSION

Population-based studies indicate that an increase in the caesarean section rate among breech singletons may be associated with increased neonatal survival, but a large multicentre randomized trial of management of breech presentation would answer the question much more definitively.

Antepartum external cephalic version with tocolysis: a study of term singleton breech presentations

External version with the use of tocolysis is cost-effective and leads to lower perinatal morbidity and a lower cesarean section rate. A study was undertaken to see if version was being practiced in a nonteaching community hospital. One hundred twenty-one breech presentations occurring at 36 or more completed weeks of gestation were reviewed from July 1, 1985 to June 30, 1986. Successful version occurred in 60% of 65 patients; 77% of patients with a successful version delivered vaginally. Six of the remaining 56 patients, who did not undergo attempted version, delivered vaginally with breech presentation. At least 21 patients who delivered by elective cesarean section would have been candidates for external version with tocolysis. Seventeen patients had a cesarean section because a breech presentation was diagnosed in labor.

Cryptorchidism, and epidemiologic study with emphasis on the relationship to central nervous system dysfunction

This case-control study examines the relation of cryptorchidism to central nervous system dysfunction. Elevated odd ratios were found for cerebral palsy (RR = 34), low IQ (RR = 2.7), and low motor function measured by the Bayley test (RR = 3.6). Low IQ and cerebral palsy were independent risk factors for cryptorchidism. Breech labor (RR = 2.6), a gestation less than 34 weeks (RR = 2.0), and being a twin (RR = 4.1) were also independent risks. Other risk factors were estrogen use by the mother (RR = 3.3) and a maternal Quetelet index less than 24 (RR = 1.6). All of these risks were statistically significant. These factors suggest that cryptorchidism may be caused either by sex steroid action directly on the testes or by CNS damage, which in turn causes suppression of pituitary gonadotropins. The increased occurrence of cryptorchidism in twins and small babies indicates that retarded general fetal development can be another mechanism for maldescent of the testes.

Method of delivery and developmental outcome at five years of age

A controlled follow-up study examined the impact of delivery method on developmental outcome of the child. The modes of delivery investigated were low forceps delivery (188 infants), midcavity forceps delivery (51 infants), forceps rotation with forceps delivery (57 infants), manual rotation with forceps delivery (67 infants), elective caesarean section (101 infants) and spontaneous delivery (control, 207 infants). Breech presentation (100 infants) was separately compared with the vertex presentation groups. Sample selection controlled for complications during pregnancy and low birthweight and was restricted to married English-speaking mothers. The children were assessed at the age of five years on verbal and non-verbal subtests of a standardized intelligence scale, tests of gross motor coordination, and auditory and visual tests. A full paediatric examination was also performed. Breech presentation children performed less well on tests of balance and fine motor coordination and on visual acuity and stereopsis testing than children who presented in the vertex position. No deleterious effect of delivery method was found. In the absence of other complicating events (like a poor antenatal history, prematurity, and a disorganized home environment) delivery complication constitutes an early risk factor which the growing child is able to overcome.

Dysmorphology: an approach to a child with structural defects

An approach to children with structural defects has been presented. The ultimate goal of this approach is a specific overall diagnosis. In such cases appropriate genetic counseling for the parents, accurate prognostication relative to the child's future development and an appropriate plan to help the child reach his potential usually are possible. When an overall diagnosis is lacking, the most that can be expected is a better understanding of the nature and onset of the problem. That in itself can often be helpful to patients and to all others dealing with children having structural defects.