MATERIALS AND METHODS
This article is about a prospective analysis, studied with 400 pregnant
women during labor between 37 and 41 weeks, and vertex presentation. We
performed this study, approved by
the local ethics committee numbered 2011-KAEK-25 2019/07-17, at the
Department of Obstetrics and Gynecology of the Bursa Yüksek İhtisas
Education and Research Hospital, Bursa, Turkey. All participants had a
confirmed estimated date of birth by first-trimester ultrasound, which
correlated with their menstrual dates.
We considered two criteria accepted by the American College of
Obstetricians and Gynaecologists (ACOG) and Royal College of
Obstetricians and Gynaecologists (RCOG) for shoulder dystocia: 1-
Failure of shoulder delivery after downward traction, 2- Deliveries
requiring maneuvers in addition to gentle downward traction on the fetal
head to effect delivery.
Nonvertex presentation, preterm labor, cesarean delivery history,
multiple gestations, before oxytocin initiation, a nonreassuring fetal
heart rate tracing, or chorioamnionitis, ablatio placenta were not
included in this study population.
Macrosomia of fetus (>4500 gram), women with gestational
diabetes, women of short stature (less than 150 cm), occiput posterior
fetal position, and history of dystocia, which are risk factors for the
conditions we mentioned, were also excluded from the study.
The digital cervical examination performed in the first stage, two-four
hours intervals, and one-two hours in the second stage. The results were
documented according to the hours and on a partogram in addition to
these records. The time from 6 cm to 10 cm and the time from complete
cervical dilation to fetal head’s expulsion recorded. Also, whether
shoulder dystocia developed at each delivery and the type of birth was
registered.
During labor, in the protracted active phase, we administered oxytocin
if not already started. However, women with labor arrest in the active
phase and the second stage had gone cesarean delivery. Otherwise, the
cesarean decision was made in cases with acute fetal distress during
follow-up.
Participants had an ultrasound examination before 6 cm cervical
dilation. Standard fetal biometry was measured, including biparietal
diameter (BPD), head circumference (HC), abdominal circumference (AC),
and femur length (FL), yielding a calculated estimated fetal weight
(EFW) using the Hadlock formula.34 Fetal adipose
tissue components consisted of the anterior abdominal wall (AAW), thigh
(femur)(FWT), and upper arm (humerus) (HWT) adipose tissue. We defined
the fetal adipose tissue composite as total adipose tissue (TATT). Total
adipose tissue components consisted of the sum of the anterior abdominal
wall, thigh, and arm adipose tissue thickness.
Fetal AAW measurement obtained at the abdominal circumference view, a
plane where the junction of the right and left fetal portal vein and
stomach seen. The image included fetal skin and subcutaneous tissue
(Figure-1). Calipers were at the echogenic area between the outer skin
edge and inner margin of the anterior abdominal wall. We calculated the
anterior abdominal wall thickness (AAWT) as the thickness of this
echogenic rim was measured at a point nearly 2 cm lateral to the
umbilical cord insertion. Three measurements were obtained, and the mean
value was recorded.
We obtained a standard image of the FL and HL, measuring fetal thigh and
arm adiposity. The calipers placed between the bones’ outer face and the
skin’s outer face in the midline. Then, another measurement was taken
from the bones’ outer edge to the inner fat surface, and the fetal
adiposity was calculated by subtracting this from the first measurement
(Figure-2)(Figure-3). Standard perinatal and obstetric data documented
during the birth.
The study’s primary outcome was to investigate if fetal adiposity was
associated with an increased risk of labor protraction or arrest.
Secondary outcomes included the effects of fetal adiposity on an
increased risk of unplanned intrapartum cesarean delivery, active phase,
second stage durations, birth weight of baby, fetus’s biometrical
parameters, and shoulder dystocia.