Overestimation of fetal weight by ultrasound: does it influence the likelihood of cesarean delivery for labor arrest?

Blackwell, Sean C.; Refuerzo, Jerrie; Chadha, Rati; Carreño, Carlos A.

doi:10.1016/j.ajog.2008.12.043

Cited by 51 publications

(57 citation statements)

References 9 publications

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“…It has been shown that labor abnormalities such as arrested labor are more likely to be diagnosed and that cesarean delivery (CD) rates are higher when fetal macrosomia is suspected, despite the real BW [8, 27–29]. Little et al [30].…”

Section: Discussionmentioning

confidence: 99%

Disadvantages of a weight estimation formula for macrosomic fetuses: the Hart formula from a clinical perspective

Weiss¹,

Oppelt²,

Mayer³

2018

Arch Gynecol Obstet

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PurposeSonographic fetal weight (FW) estimation to detect macrosomic fetuses is an essential part of everyday routine work in obstetrics departments. Most of the commonly used weight estimation formulas underestimate FW when the actual birth weight (BW) exceeds 4000 g. One of the best-established weight estimation formulas is the Hadlock formula. In an effort to improve the detection rates of macrosomic infants, Hart et al. published a specially designed formula including maternal weight at booking. The usefulness of the Hart formula was tested.MethodsRetrospective study of 3304 singleton pregnancies, birth weight ≥ 3500 g. The accuracy of the Hadlock and Hart formula were tested. A subgroup analysis examined the influence of the maternal weight. The Chi-squared test and one-way analysis of variation were carried out. For all analyses, p < 0.05 was considered statistically significant.ResultsThe overall percentages of births falling within ± 5% and ± 10% of the BW using the Hadlock formula were 27% and 53%, respectively. Using the Hart formula, 24% and 54% were identified within these levels. With the Hart formula, 94% of all weight estimations fall within 4200 g ± 5% and nearly 100% fall within 4200 g ± 10%.ConclusionsApplying the Hart formula results in an overestimation of fetal weight in neonates with a birth weight < 4000 g and fails to identify high-risk fetuses. We, therefore, do not consider Hart’s formula to be of clinical relevance.

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Section: Discussionmentioning

confidence: 99%

Disadvantages of a weight estimation formula for macrosomic fetuses: the Hart formula from a clinical perspective

Weiss¹,

Oppelt²,

Mayer³

2018

Arch Gynecol Obstet

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“…For example, one study of women induced at term suggested that clinicians who anticipate fetal macrosomia diagnose labor arrest at lower thresholds, increasing cesarean delivery rates (21). We found that more than one in three mothers with SLBs noted concerns with the baby’s size as the reason their maternity provider induced labor, the second-most commonly cited reason for induction among cases of medically-induced labor.…”

Section: Discussionmentioning

confidence: 99%

“…These findings are important in light of ACOG guidelines (7) and empirical evidence that such interventions do not reduce neonatal morbidities for SLBs. (8, 15–21)…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have found a “suspected large baby” to be associated with interventions such as induction of labor and cesarean delivery. (8, 15–21) These studies were conducted in clinic-based or non-US samples, which may preclude the generalizability of findings to the US population as a whole. Therefore, we characterized the prevalence of and factors associated with clinicians’ prenatal suspicion of a large baby and determined whether communicating fetal size concerns to patients was associated with select labor and delivery interventions and outcomes using a nationally representative sample of US women.…”

Section: Introductionmentioning

confidence: 99%

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Labor and Delivery Experiences of Mothers with Suspected Large Babies

Declercq

Belanoff

Stotland

et al. 2015

Matern Child Health J

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Objective To characterize the prevalence of and factors associated with clinicians’ prenatal suspicion of a large baby; and to determine whether communicating fetal size concerns to patients was associated with labor and delivery interventions and outcomes. Methods We examined data from women without a prior cesarean who responded to Listening to Mothers III, a nationally representative survey of women who had given birth between July 2011 and June 2012 (n=1,960). We estimated the effect of having a suspected large baby (SLB) on the odds of six labor and delivery outcomes. Results Nearly one-third (31.2%) of women were told by their maternity care providers that their babies might be getting “quite large”; however, only 9.9% delivered a baby weighing ≥4,000 grams (19.7% among mothers with SLBs, 5.5% without). Women with SLBs had increased adjusted odds of medically-induced labor (AOR 1.9; 95% CI: 1.4–2.6), attempted self-induced labor (AOR 1.9; 95% CI: 1.4–2.7), and use of epidural analgesics (AOR 2.0; 95% CI: 1.4–2.9). No differences were noted for overall cesarean rates, although women with SLBs were more likely to ask for (AOR 4.6; 95% CI: 2.8–7.6) and have planned (AOR 1.8; 95% CI: 1.0–4.5) cesarean deliveries. These associations were not affected by adjustment for gestational age and birthweight. Conclusion Only one in five US women who were told that their babies might be getting quite large actually delivered infants weighing ≥4,000 grams. However, the suspicion of a large baby was associated with an increase in perinatal interventions, regardless of actual fetal size.

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“…It is important to optimize the identification of LGA fetuses in utero at term if one hopes to prevent maternal or neonatal complications by recommending a policy of induced labor before 39 weeks and to avoid futile medicalization of a pregnancy for which fetal weight was overestimated. These misestimates of fetal weight can result in greater recourse to cesareans [43,44]. Moreover, the methods for estimating fetal weight, especially macrosomia, remain unreliable [45,46].…”

Section: Discussionmentioning

confidence: 99%

Does induction of labor for constitutionally large-for-gestational-age fetuses identified in utero reduce maternal morbidity?

Vendittelli

Rivière²,

Neveu

et al. 2014

BMC Pregnancy Childbirth

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BackgroundThe number of infants with a birth weight > 97th percentile for gestational age has increased over the years. Although some studies have examined the interest of inducing labor for fetuses with macrosomia suspected in utero, only a few have analyzed this suspected macrosomia according to estimated weight at each gestational age. Most studies have focused principally on neonatal rather than on maternal (and still less on perineal) outcomes. The principal aim of this study was to assess whether a policy of induction of labor for women with a constitutionally large-for-gestational-age fetus might reduce the occurrence of severe perineal tears; the secondary aims of this work were to assess whether this policy would reduce either recourse to cesarean delivery during labor or neonatal complications.MethodsThis historical cohort study (n = 3077) analyzed records from a French perinatal database. Women without diabetes and with a cephalic singleton term pregnancy were eligible for the study. We excluded medically indicated terminations of pregnancy and in utero fetal deaths. Among the pregnancies with fetuses suspected, before birth, of being large-for-gestational-age, we compared those for whom labor was induced from ≥ 37 weeks to ≤ 38 weeks+ 6 days (n = 199) to those with expectant obstetrical management (n = 2878). In this intention-to-treat analysis, results were expressed as crude and adjusted relative risks.ResultsThe mean birth weight was 4012 g ± 421 g. The rate of perineal lesions did not differ between the two groups in either primiparas (aRR: 1.06; 95% CI: 0.86-1.31) or multiparas (aRR: 0.94; 95% CI: 0.84-1.05). Similarly, neither the cesarean rate (aRR: 1.11; 95% CI: 0.82-1.50) nor the risks of resuscitation in the delivery room or of death in the delivery room or in the immediate postpartum or of neonatal transfer to the NICU (aRR = 0.94; 95% CI: 0.59-1.50) differed between the two groups.ConclusionsA policy of induction of labor for women with a constitutionally large-for-gestational-age fetus among women without diabetes does not reduce maternal morbidity.

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Overestimation of fetal weight by ultrasound: does it influence the likelihood of cesarean delivery for labor arrest?

Cited by 51 publications

References 9 publications

Disadvantages of a weight estimation formula for macrosomic fetuses: the Hart formula from a clinical perspective

Disadvantages of a weight estimation formula for macrosomic fetuses: the Hart formula from a clinical perspective

Labor and Delivery Experiences of Mothers with Suspected Large Babies

Does induction of labor for constitutionally large-for-gestational-age fetuses identified in utero reduce maternal morbidity?

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