Fetal head circumference, operative delivery, and fetal outcomes: a multi-ethnic population-based cohort study

Abstract

BackgroundOperative delivery procedures, such as primary cesarean section, vacuum-assisted, and forceps-assisted vaginal delivery increase maternal and fetal morbidity, and the cost of care. We evaluated whether large fetal head circumference (FHC) independently increases risk of such interventions, as well as fetal distress or low Apgar score, in anatomically normal infants.MethodsWe conducted a population-based retrospective cohort study using Washington State birth certificate data. We included singleton, term infants born to nulliparous mothers from 2003–2009. We compared mode of delivery and fetal outcomes in 10,750 large-FHC (37-41 cm) infants relative to 10,750 average-FHC (34 cm) infants, frequency matched by birth-year.ResultsLarge-FHC infants were nearly twice as likely to be delivered by primary cesarean section as average-FHC infants (unadjusted relative risk [RR] 1.84, 95% confidence interval [CI]: 1.77, 1.92). The RR for primary cesarean section associated with large-FHC was largest for mothers aged 19 years or less (RR 2.28; 95% CI: 1.99, 2.61), and smallest for mothers aged 35 years or greater (RR 1.51; 95% CI: 1.37, 1.66) [test of homogeneity, p < 0.001]. Large-FHC infants were at increased risk of vacuum-assisted vaginal delivery (RR 1.55; 95% CI: 1.43, 1.69), and forceps-assisted vaginal delivery (RR 1.61; 95% CI: 1.32, 1.97). There was no difference in risk of fetal distress (RR 0.97; 95% CI: 0.89, 1.07) for large-FHC versus average-FHC infants. Risk estimates were unaffected by adjustment for potential confounders.ConclusionsNulliparous mothers of large-FHC infants are at increased risk of primary cesarean section, vacuum-assisted and forceps-assisted vaginal delivery relative to mothers of average-FHC infants. Maternal age modifies the association between FHC and primary cesarean section.

Safe Childbirth and Motherhood in African Great Lakes Region: External Pelvimetry in Nulliparae and Scheduled Caesarean Section

“…In one hand, newborn death, uterine rupture and obstetric fistula are among complications with the saddest impact on a surviving primiparous woman and her family with regard to the pronatalist African culture. In the other hand, cephalopelvic disproportion due to generally contracted pelvis or large foetal head circumference is one of caesarean section indications in nulliparae and pregnant women aged less than 19 [17][18][19][20]; and this should also be the case in settings characterised by early marriages and lack of appropriate pregnancy monitoring. Besides, it is also known that external pelvimetry is nowadays controversial and no longer in favour with many obstetricians [21,22], now that new, more powerful diagnostic tools, e.g.…”

A large head circumference is more strongly associated with unplanned cesarean or instrumental delivery and neonatal complications than high birthweight

“…Few studies have investigated the impact of head circumference on the odds of operative delivery in nulliparae; [6][7][8]10 rather focusing on estimated fetal weight. 11 The earlier studies showed that the odds of operative delivery and prolonged second stage of labor 6-8 increased as HC increased, and found as we did that infants of higher birth weight were less likely to show signs of fetal distress than smaller fetuses with similar HC 6 .…”

“…the tension at the point of meeting of the human fetal head and the bipedal female pelvis, [1][2][3][4] but sparse attention has been paid in the obstetric literature to the impact of head circumference on obstetric outcomes. [5][6][7][8][9][10] The literature on problems of delivery in "big babies" focuses primarily on fetal size in terms of weight. [11][12][13][14] We queried how fetal head dimensions might impact the passage of the fetus through the birth canal and affect obstetric outcomes, primarily delivery mode.…”

Accuracy of birth certificate head circumference measurements: Massachusetts, 2012–2013

“…Several prior studies have used head circumference data obtained from the birth certificate to evaluate infant and maternal health outcomes (Krstev, Marinković, Simić, Kocev, & Bondy, 2013;Mujugira, Osoti, Deya, Hawes, & Phipps, 2013). To our knowledge, there is not a study available that has investigated the accuracy of birth certificate head circumference data.…”