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

doi:10.1016/j.ajog.2015.07.045

American Journal of Obstetrics and Gynecology

Volume 213, Issue 6, December 2015, Pages 833.e1-833.e12

Presented at the annual meeting of the Israel Society of Maternal-Fetal Medicine, November 5–6, 2014, and the Annual Conference of the Society of Reproductive Investigation, March 25–28, 2015.

https://doi.org/10.1016/j.ajog.2015.07.045 Get rights and content

Objective

Fetal size impacts on perinatal outcomes. We queried whether the fetal head, as the fetal part interfacing with the birth canal, might impact on obstetric outcomes more than birthweight (BW). We examined associations between neonatal head circumference (HC) and delivery mode and risk of perinatal complications as compared to high BW.

Study Design

This was an electronic medical records–based study of term singleton births (37-42 weeks’ gestation) from January 2010 through December 2012 (N = 24,780, 6343 primiparae). We assessed risks of unplanned cesarean or instrumental delivery and maternal and fetal complications in cases with HC or BW ≥95th centile (large HC, high BW) vs those with parameters <95th centile (normal). Newborns were stratified into 4 subgroups: normal HC/normal BW (reference, n = 22,548, primiparae 5862); normal HC/high BW (n = 817, P = 213); large HC/normal BW (n = 878, P = 265); and large HC/high BW (n = 537, P = 103). Multinomial multivariable regression provided adjusted odds ratio (aOR) while controlling for potential confounders.

Results

Infants with HC ≥95th centile (n = 1415) were delivered vaginally in 62% of cases, unplanned cesarean delivery 16%, and instrumental delivery 11.2%; 78.4% of infants with HC <95th centile were delivered vaginally, 7.8% unplanned cesarean, and 6.7% instrumental delivery. Odds ratio (OR) for unplanned cesarean was 2.58 (95% confidence interval [CI], 2.22–3.01) and for instrumental delivery OR was 2.13 (95% CI, 1.78–2.54). In contrast, in those with BW ≥95th centile (n = 1354) 80.3% delivered vaginally, 10.2% by unplanned cesarean (OR, 1.2; 95% CI, 1.01–1.44), and 3.4% instrumental delivery (OR, 0.46; 95% CI, 0.34–0.62) compared to infants with BW <95th centile: spontaneous vaginal delivery, 77.3%, unplanned cesarean 8.2%, instrumental 7.1%. Multinomial regression with normal HC/normal BW as reference group showed large HC/normal BW infants were more likely to be delivered by unplanned cesarean (aOR, 3.08; 95% CI, 2.52–3.75) and instrumental delivery (aOR, 3.03; 95% CI, 2.46–3.75). Associations were strengthened in primiparae. Normal HC/high BW was not associated with unplanned cesarean (aOR, 1.18; 95% CI, 0.91–1.54), while large HC/high BW was (aOR, 1.93; 95% CI, 1.47–2.52). Analysis of unplanned cesarean indications showed large HC infants had more failure to progress (27.7% vs 14.1%, P < .001), while smaller HC infants had more fetal distress (23.4% vs 16.9%, P < .05).

Conclusion

A large HC is more strongly associated with unplanned cesarean and instrumental delivery than high BW. Prospective studies are needed to test fetal HC as a predictive parameter for prelabor counseling of women with “big babies.”

Section snippets

Materials and Methods

This was a cross-sectional study based on EMR performed in the Hadassah-Hebrew University Medical Centers Jerusalem, comprising 2 campuses of a tertiary care center. Our institutional ethical review board reviewed and approved the study (#0085-13-HMO; Feb. 14, 2013). All singleton term deliveries (37⁺⁰-42⁺⁰) occurring from January 2010 through December 2012 were eligible for inclusion. Multiple births were excluded. Data were collected in blinded fashion by research staff who were not involved

Results

A total of 28,168 term singleton deliveries occurred at our hospitals during the study period. Electronic data for HC and/or BW were missing in a small number of files: 1588 (5.6%) had no HC, 20 (0.07%) no BW, and 8 had neither parameter recorded. These cases were excluded from further analysis. The remaining cohort of 26,560 was analyzed for percentiles cutoffs; infants found to have HC and/or BW ≤5th centile were excluded from further analysis. A total of 24,780 singleton births therefore

Principal findings of the study

In this study based on high-quality EMRs with data entered prospectively prepartum, intrapartum, and postpartum, we demonstrate that large HC showed stronger association as compared to high BW with perinatal complications. We showed that infants with HC ≥95th centile had higher risk for interventional delivery (instrumental or UCD). Large HC infants were delivered by UCD about twice as frequently as those with HC in normal range, regardless of BW. Among infants of primiparae the risk was

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Cited by (72)

Factors associated with spontaneous vaginal birth in nulliparous women: A descriptive systematic review
2024, Women and Birth
Spontaneous vaginal birth (SVB) rates for nulliparous women are declining internationally.
There is inadequate understanding of factors affecting this trend overall and limited large-scale responses to improve women's opportunity to birth spontaneously.
To undertake a descriptive systematic review identifying factors associated with spontaneous vaginal birth at term, in nulliparous women with a singleton pregnancy.
Quantitative studies of all designs, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a SVB at term were included. Nine databases were searched (inception to October 2022). Two reviewers undertook quality appraisal; Randomised Controlled Trials (RCTs) with high risk of bias (ROB 2.0) and other designs with (QATSDD) scoring ≤ 50% were excluded.
Data were abstracted from 90 studies (32 RCTs, 39 cohort, 9 cross-sectional, 4 prevalence, 5 case control, 1 quasi-experimental). SVB rates varied (13%−99%). Modifiable factors associated with SVB included addressing fear of childbirth, low impact antenatal exercise, maternal positioning during second-stage labour and midwifery led care. Complexities arising during pregnancy and regional analgesia were shown to decrease SVB and other interventions, such as routine induction of labour were equivocal.
Antenatal preparation (low impact exercise, childbirth education, addressing fear of childbirth) may increase SVB, as does midwifery continuity-of-care. Intrapartum strategies to optimise labour progression emerged as promising areas for further research.
Declining SVB rates may be improved through multi-factorial approaches inclusive of maternal, fetal and clinical care domains. However, the variability of SVB rates testifies to the complexity of the issue.
Sex-specific differences in head circumference of term singletons after assisted reproductive technology: a multicentre study in Japan
2023, Reproductive BioMedicine Online
Does fertility treatment, specifically assisted reproductive technology (ART), affect head circumference in term singletons?
A total of 32,651 women who delivered at term at 12 maternity hospitals in Japan between 2010 and 2018 were included in the analysis; of these, 1941 (5.9%) and 2984 (9.1%) women conceived through ART and non-ART fertility treatments (timed intercourse, ovulation induction or artificial insemination), respectively. The study evaluated the adjusted odds ratios of head circumference ≥90th percentile stratified by infant sex and type of ART procedure after adjusting for covariates, with natural conception as the reference group.
ART significantly increased the risk of head circumference ≥90th percentile (adjusted odds ratio 1.56 [95% confidence interval 1.25–1.96]), whereas non-ART fertility treatment did not increase the risk (1.14 [0.92–1.42]). This increased risk of head circumference ≥90th percentile was observed exclusively in male neonates (1.73 [1.33–2.26]) and not in female neonates (1.18 [0.76–1.85]) in the ART group. Frozen embryo transfer (FET), FET in a hormone replacement cycle (HRC-FET) and blastocyst-stage embryo transfer were significantly associated with head circumference ≥90th percentile (1.60 [1.26–2.02], 1.70 [1.30–2.22] and 1.72 [1.33–2.24], respectively).
The use of ART, particularly FET, HRC-FET or blastocyst-stage embryo transfer, was linked with a heightened risk of head circumference ≥90th percentile compared with non-ART fertility treatment or natural conception. The increased risk was observed only in male neonates.
Magnetic resonance imaging pelvimetric measurements as predictors for emergent cesarean delivery in obstructed labor
2023, European Journal of Obstetrics and Gynecology and Reproductive Biology: X
This study aimed to investigate the usefulness of various magnetic resonance imaging (MRI) pelvimetric parameters for predicting emergent cesarean delivery due to obstructed labor.
This was a prospective observational study. MRI pelvimetry was performed in cases of a clinically suspected maternal narrow pelvis, maternal short stature, fetal overgrowth, and abnormal placental position. MRI pelvimetry was performed at 34.7 ± 4.2 gestational weeks using a 1.5 T MRI system. The pelvic inlet angle, pelvic inclination, obstetric conjugate, sacral outlet diameter (SOD), and coccygeal pelvic outlet were measured in the sagittal section. The interspinous diameter and intertuberous diameter were measured in coronal sections. Fetal anomalies, cesarean deliveries before the onset of labor, and non-reassuring fetal status were excluded from the analysis.
MRI pelvimetry was performed in 154 patients. After excluding 76 cases, including 19 cases of absolute cephalopelvic disproportion, 78 cases of trial of labor were included. Of these, 63 were vaginal deliveries and 15 were emergent cesarean deliveries due to obstructed labor. The cut-off value for body mass index (BMI) was 22.2, with an area under the curve (AUC) of 0.69, for predicting obstructed labor. The cut-off value for the SOD was 10.7 cm with an AUC of 0.69. BMI alone had a sensitivity of 80%, specificity of 66%, positive predictive value (PPV) of 36%, and negative predictive value (NPV) of 93%. When BMI and SOD were combined, sensitivity was 53%, specificity was 90%, PPV was 57%, and NPV was 89%. The odds ratio for emergent cesarean delivery was 5.42 (95% confidence interval 1.06–27.6, p = 0.041) if the SOD was less than the cut-off value in the binomial logistic regression analysis in cases with an BMI > 22.
We confirmed that MRI pelvimetry was a reliable tool for better patient selection for obstructed labor. The SOD was the best predictor of obstructed labor, with a cut-off value of 10.7 cm for women with a low BMI.
The sonographic measurement of the ratio between the fetal head circumference and the obstetrical conjugate is accurate in predicting the risk of labor arrest: results from a multicenter prospective study
2022, American Journal of Obstetrics and Gynecology MFM
Labor arrest is estimated to account for approximately one-third of all primary cesarean deliveries, and is associated with an increased risk of adverse maternal and perinatal outcomes. One of the main causes is the mismatch between the size of the birth canal and that of the fetus, a condition usually referred to as cephalopelvic disproportion.
This study aimed to describe a new ultrasound predictor of labor arrest leading to cesarean delivery because of suspected cephalopelvic disproportion.
This was a multicenter prospective study conducted at 3 maternity units from January 2021 to January 2022. A nonconsecutive series of singleton pregnancies with cephalic-presenting fetuses, gestational age of 34 weeks+0 days or above, and no contraindication to vaginal delivery attending at the antenatal clinics of each institution were considered eligible. Between 34+0 and 38+0 weeks of gestation, all eligible patients were submitted to transabdominal 2D ultrasound measurement of the obstetrical conjugate. On admission to the labor ward, the fetal head circumference was measured on the standard transthalamic plane by transabdominal ultrasound. The primary outcome of the study was the accuracy of the ratio between the fetal head circumference and the obstetrical conjugate measurement (ie, head circumference/obstetrical conjugate ratio) in predicting the occurrence of cesarean delivery secondary to labor arrest. The secondary outcome was the relationship between the head circumference/obstetrical conjugate ratio and labor duration.
A total of 263 women were included. Cesarean delivery for labor arrest was performed in 7.6% (20/263) of the included cases and was associated with more frequent use of epidural analgesia (95.0% vs 45.7%; P<.001), longer second stage of labor (193 [120–240] vs 34.0 [13.8–66.5] minutes; P=.002), shorter obstetrical conjugate (111 [108–114] vs 121 [116–125] mm; P<.001), higher head circumference/obstetrical conjugate ratio (3.2 [3.2–3.35] vs 2.9 [2.8–3.0]; P<.001), and higher birthweight (3678 [3501–3916] vs 3352 [3095–3680] g; P=.003) compared with vaginal delivery. At logistic regression analysis, the head circumference/obstetrical conjugate ratio expressed as Z-score was the only parameter independently associated with risk of cesarean delivery for labor arrest (odds ratio, 8.8; 95% confidence interval, 3.6–21.7) and had higher accuracy in predicting cesarean delivery compared with the accuracy of fetal head circumference and obstetrical conjugate alone, with an area under the curve of 0.91 (95% confidence interval, 81.7–99.5; P<.001). A positive correlation between the head circumference/obstetrical conjugate ratio and length of the second stage of labor was found (Pearson coefficient, 0.16; P=.018).
Our study, conducted on an unselected low-risk population, demonstrated that the head circumference/obstetrical conjugate ratio is a reliable antenatal predictor of labor arrest leading to cesarean delivery.
Association between birth weight and head circumference and obstetric anal sphincter injury severity
2021, European Journal of Obstetrics and Gynecology and Reproductive Biology
Citation Excerpt :
Several studies have investigated long term complications following OASI and found higher rates of anal incontinence and reduced sphincter tone in major (3c and 4th degree) perineal tears [6–9], while others observed no correlation between the extent of the anal sphincter defect and severity of fecal incontinence [10]. Although previous studies have investigated risk factors for pelvic floor disorders and OASI, such as nulliparity [11–16], operative vaginal delivery [16–21], birth weight (BW) [14–18] and head circumference (HC)[18,22] and presented prediction models for OASI [23], their focus was mostly on the occurrence of OASI as a sole outcome, without a specific evaluation of the anal sphincter tear degree and the unique risk factors for each degree. Few studies have categorized OASI into minor (3a-3b) and major injuries (3c and 4) [24]; however, a paucity of data exists on OASI risk factors with regard to the specific sub-categories of third-degree tear.
To identify risk factors for increasing severity of OASI and evaluate its possible correlation with two known risk factors–birth weight (BW) and neonatal head circumference (HC).
We performed a retrospective cohort study at a university affiliated hospital between 2003 and 2019. We compared five groups of patients – according to presence and degree of perineal laceration – 3a, 3b, 3c and 4 and patients without OASI. Additionally, four parameters were defined to assess their relation to the severity of OASI: (1) BW ≥ 90th and HC < 90th percentiles; (2) BW < 90th and HC ≥ 90th percentile; (3) BW and HC ≥ 90th percentile and (4) BW and HC < 90th percentiles.
During the study period, 150,221 deliveries were evaluated. Parturients were allocated according to OASI severity − 455 patients had a 3rd (3a, 3b or 3c) or 4th degree perineal tear, while 110,966 patients had no OASI. Allocation to subgroups according to offspring anthropomorphic measures showed that as fetal size parameters increased, the rate of more severe tears increased, particularly in women delivering neonates with HC ≥ 90th percentile.
Multinomial regression analysis was performed for each 3rd degree OASI subgroup. This analysis demonstrated the odds for OASI gradually increase with tear severity for BW ≥ 90th percentile and the combined BW and HC ≥ 90th percentile parameters, as compared with neonates with HC and BW < 90th percentile.
Birth weight and head circumference above the 90th percentile are correlated with increased degree of OASI severity.
Intrapartum sonographic assessment of the fetal head flexion in protracted active phase of labor and association with labor outcome: a multicenter, prospective study
2021, American Journal of Obstetrics and Gynecology
Citation Excerpt :
We do envisage that in these conditions any attempt to perform an instrumental VD should be balanced against the risks of “true” obstructed labor. However, more research is required to clarify whether the head circumference,48,49 the maternal height,50–53 or other sonographic indices may be considered in the individualized management of the laboring woman diagnosed as having protracted active phase of labor in cases characterized by non-OP position, wide OSA, narrow AoP, and long HPD. Regarding the degree of flexion of the fetal head in OP fetuses, this study describes a quantitative parameter—that is, the CCA—for the assessment of the degree of flexion of the fetal head, which we show to be associated with a fair sensitivity and NPV in the prediction of CD owing to labor dystocia.
To date, no research has focused on the sonographic quantification of the degree of flexion of the fetal head in relation to the labor outcome in women with protracted active phase of labor.
This study aimed to assess the relationship between the transabdominal sonographic indices of fetal head flexion and the mode of delivery in women with protracted active phase of labor.
Prospective evaluation of women with protracted active phase of labor recruited across 3 tertiary maternity units. Eligible cases were submitted to transabdominal ultrasound for the evaluation of the fetal head position and flexion, which was measured by means of the occiput-spine angle in fetuses in nonocciput posterior position and by means of the chin-to-chest angle in fetuses in occiput posterior position. The occiput-spine angle and the chin-to-chest angle were compared between women who had vaginal delivery and those who had cesarean delivery. Cases where obstetrical intervention was performed solely based on suspected fetal distress were excluded.
A total of 129 women were included, of whom 43 (33.3%) had occiput posterior position. Spontaneous vaginal delivery, instrumental delivery, and cesarean delivery were recorded in 66 (51.2%), 17 (13.1%), and 46 (35.7%) cases, respectively. A wider occiput-spine angle was measured in women who had vaginal delivery compared with those submitted to cesarean delivery owing to labor dystocia (126±14 vs 115±24; P<.01). At the receiver operating characteristic curve, the area under the curve was 0.675 (95% confidence interval, 0.538–0.812; P<.01), and the optimal occiput-spine angle cutoff value discriminating between cases of vaginal delivery and those delivered by cesarean delivery was 109°. A narrower chin-to-chest angle was measured in cases who had vaginal delivery compared with those undergoing cesarean delivery (27±33 vs 56±28 degrees; P<.01). The area under the curve of the chin-to-chest angle in relation to the mode of delivery was 0.758 (95% confidence interval, 0.612–0.904; P<.01), and the optimal cutoff value discriminating between vaginal delivery and cesarean delivery was 33.0°.
In women with protracted active phase of labor, the sonographic demonstration of fetal head deflexion in occiput posterior and in nonocciput posterior fetuses is associated with an increased incidence of cesarean delivery owing to labor dystocia. Such findings suggest that intrapartum ultrasound may contribute in the categorization of the etiology of labor dystocia.

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: The authors report no conflict of interest.

: Cite this article as: Lipschuetz M, Cohen SM, Ein-Mor E, et al. A large head circumference is more strongly associated with unplanned cesarean or instrumental delivery and neonatal complications than high birthweight. Am J Obstet Gynecol 2015;213:833.e1-12.

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

Objective

Study Design

Results

Conclusion

Section snippets

Materials and Methods

Results

Principal findings of the study

BJOG

Am J Obstet Gynecol

Am J Obstet Gynecol

Am J Obstet Gynecol

Am J Obstet Gynecol

Eur J Obstet Gynecol Reprod Biol

Eur J Obstet Gynecol Reprod Biol

Am J Obstet Gynecol

Am J Obstet Gynecol

Lancet Diabet Endocrinol

Lancet

The evolutionary origins of obstructed labor: bipedalism, encephalization, and the human obstetric dilemma

Obstet Gynecol Surv

The obstetric dilemma: an ancient game of Russian roulette, or a variable dilemma sensitive to ecology?

Am J Phys Anthropol

Between Scylla and Charybdis: renegotiating resolution of the ‘obstetric dilemma' in response to ecological change

Philos Trans R Soc Lond B Biol Sci

The influence of fetal head circumference on labor outcome: a population-based register study

Acta Obstet Gynecol Scand

Postpartum fetal head circumference and its influence on labor duration in nullipara

J Obstet Gynaecol

Association of head circumference and shoulder dystocia in macrosomic neonates

Matern Child Health J

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