Antonina Frolova

• MD, PhD
• Professor (Assistant) at Washington University in St. Louis

Approximately half of U.S. women giving birth annually receive Pitocin, a synthetic form of oxytocin (OXT), yet the optimal dosing remains challenging due to significant individual variability in response. To address this, we developed a mathematical model examining the effects of five OXT receptor (OXTR) variants (V45L, P108A, L206V, V281M, and E3...

Approximately half of U.S. women giving birth annually receive Pitocin, the synthetic form of oxytocin (OXT), yet its effective dose can vary significantly. To address the need for improved dosing, we developed a data-driven mathematical model to predict OXT receptor (OXTR) binding. Our study focuses on five prevalent OXTR variants (V45L, P108A, L2...

( Am J Obstet Gynecol . 2023;229(4):449.e1–449.e6. doi: 10.1016/j.ajog.2023.04.018) Anemia is a common co-occurring diagnosis in pregnancy that is associated with an increased risk of several adverse pregnancy outcomes, including fetal growth restriction, preterm labor, and perinatal death. Prior studies demonstrated that maternal and fetal physiol...

Objectives Estimated fetal weight (EFW) is an important metric at delivery as neonates with abnormal birthweight and their mothers are at higher risk of birth complications. Data regarding optimal EFW assessment in gravidas with obesity is inconsistent, and with the increasing incidence of obesity, clarification of this question is crucial. We aime...

Over 35% of reproductive-age women in the US are obese, putting them at increased risk for numerous obstetric complications due to abnormal labor. While the association between maternal obesity and abnormal labor has been well documented, the mechanisms responsible for this remain understudied. The uterine smooth muscle, myometrium, has high energy...

Approximately half of U.S. women giving birth annually receive Pitocin, the synthetic form of oxytocin(OXT), yet its effective dose can vary significantly, presenting safety concerns due to unpredictable responses, which may lead to adverse outcomes for both mother and baby. To address the need for improved dosing, we developed a data-driven mathem...

Oxytocin acts through the oxytocin receptor (OXTR) to modulate uterine contractility. We previously identified OXTR genetic variants and showed that, in HEK293T cells, two of the OXTR protein variants localized to the cell surface less than wild-type OXTR. Here, we sought to measure OXTR in the more native human myometrial smooth muscle cell (HMSMC...

OBJECTIVE To estimate the effect of diabetes group prenatal care on rates of preterm birth and large for gestational age (LGA) among patients with diabetes in pregnancy compared with individual diabetes prenatal care. DATA SOURCES We searched Ovid Medline (1946–), Embase.com (1947–), Scopus (1823–), Cochrane Central Register of Controlled Trials,...

Background: Non-reassuring fetal status detected by continuous electronic fetal monitoring accounts for almost 1 in 4 primary cesarean deliveries. However, given the subjective nature of the diagnosis there is a need to identify the electronic fetal monitoring patterns which are clinically considered non-reassuring. Objective: We sought to descr...

( Am J Obstet Gynecol . 2022;227:513.e1–513.e8) Infection- or noninfection-mediated intrapartum maternal fever (≥38 °C) is a frequent complication of childbirth, affecting 1 in 15 deliveries. Associations with increased risk for neonatal morbidity include low Apgar score, sepsis, encephalopathy, seizures, respiratory distress, meconium aspiration,...

Objective: There is evidence to suggest that early amniotomy during induction of labor is advantageous. However, following cervical ripening balloon removal the cervix remains less effaced and the utility of amniotomy in this setting is less clear. We investigated whether cervical effacement at the time of amniotomy impacts outcomes among nullipar...

Background: Electronic fetal monitoring is widely used to identify and intervene on suspected fetal hypoxia and/or acidemia. Category II fetal heart rate tracings (FHTs) are the most common class of fetal monitoring in labor, and intrauterine resuscitation is recommended given the association of Category II FHTs with fetal acidemia. However, minim...

INTRODUCTION In March 2020, the American College of Obstetricians and Gynecologists updated recommendations for prelabor preterm rupture of membranes (PPROM) at 34 weeks 0 days–36 weeks 6 days to include shared decision-making (SDM) for expectant management (EM) versus immediate delivery (ID). We sought to compare the patient populations offered EM...

One of the common mechanisms responsible for obstetric complications, affecting millions of women every year, is abnormal uterine contractility. Despite the critical importance of this process for women's health, mechanisms of uterine contraction regulation remain poorly understood. The initiation of uterine smooth muscle (myometrial) contraction i...

Background: Anemia is a commonly diagnosed comorbidity in pregnancy that is associated with an increased risk of maternal and neonatal complications. Recent data demonstrate that maternal anemia was associated with higher umbilical artery and umbilical vein O2 content at the time of delivery. Objective: We examined the relationship between mater...

Background: The second stage of labor requires active patient engagement. Prior studies suggest that coaching can influence second stage duration. However, a standardized education tool has not been established and patients face many barriers to accessing childbirth education before delivery OBJECTIVE: We investigated the effect of an intrapartum...

Objective: Internal contraction monitoring provides a quantitative assessment of intrauterine resting tone. During the course of labor elevated intrauterine resting tone may be identified. We hypothesized that elevated intrauterine resting tone could lead to compression of the spiral arteries, thus limiting uterine blood flow and resulting in neon...

Objective: To investigate the relationship between maternal serum lipid parameters and oxytocin requirements among women with term vaginal deliveries. Study design: In this secondary analysis of a prospective cohort study, women who presented for delivery at ≥37 weeks gestation and received oxytocin during their labor were included. Maternal ser...

Background Cesarean delivery (CD) is the most performed major surgery in women and surgical site infections following CD are a significant source of postoperative morbidity. It is unclear whether vaginal cleansing prior to cesarean delivery decreases post-cesarean infectious morbidity. Objective To evaluate whether preoperative vaginal cleansing w...

Objective: To estimate short-term maternal and neonatal outcomes with one-compared with two-step testing for gestational diabetes mellitus (GDM). Data sources: A systematic review of randomized controlled trials (RCTs) and observational studies comparing one-step and two-step GDM testing strategies before September 2021 was conducted. We searche...

Objective Maternal obesity is a risk factor for stillbirth, but whether or not the etiology of stillbirth differs in gravidas with and without obesity is unknown. We categorized stillbirths in a contemporary cohort to test the hypothesis that the etiology of stillbirth is different in gravidas with and without obesity. Methods This retrospective c...

Diabetes and pregnancy are independently associated with increased risk of severe COVID-infection. However, little is known about the relationship between severe COVID-and diabetes in pregnancy. We sought to determine whether diabetes in pregnancy was associated with increased risk of COVID-infection and severity. We conducted a case-control study...

Background Umbilical artery absent end-diastolic velocity (AEDV) indicates increased placental resistance and is associated with increased risk of perinatal demise and neonatal morbidity in fetal growth restriction (FGR). However, the clinical implications of intermittent (iAEDV) versus persistent (pAEDV) absent end-diastolic velocity are unclear....

Background The few studies that have addressed the relationship between severity of intrapartum fever and neonatal and maternal morbidity have mixed results. The impact of the duration between maximum intrapartum temperature and delivery on neonatal outcomes remains unknown. Objective To test the association between severity of intrapartum fever a...

Objective: Internal contraction monitoring during the course of labor may identify elevated intrauterine resting tone. Our objective was to assess the association between elevated resting tone during labor and neonatal morbidity. Design: Secondary analysis of a prospective cohort study. Setting and Population: Term singleton patients with ruptured...

Oxytocin is a potent uterotonic agent administered to nearly all patients during childbirth in the United States. Inadequate oxytocin response can necessitate Cesarean delivery or lead to uterine atony and postpartum hemorrhage. Thus, it may be clinically useful to identify patients at risk for poor oxytocin response and develop strategies to sensi...

The hormone oxytocin is commonly administered during childbirth to initiate and strengthen uterine contractions and prevent postpartum hemorrhage. However, patients have wide variation in the oxytocin dose required for a clinical response. To begin to uncover the mechanisms underlying this variability, we screened the 11 most prevalent missense gen...

Objective Many research studies in the United States came to an abrupt halt when the World Health Organization declared the Coronavirus 2019 (COVID-19) pandemic in March 2020, including ongoing perinatal studies addressing national rates of maternal and fetal morbidity. Research on Labor & Delivery units (L&D) was particularly vulnerable to setback...

Background Physical activity in pregnancy is associated with decreased risks of adverse pregnancy outcomes such as gestational diabetes and preeclampsia. However, the relationship between amount and type physical activity during pregnancy and subsequent labor outcomes is unknown. Objective We tested the hypothesis that higher levels of physical ac...

Background The maternal habitus in the setting of obesity makes external monitoring of the fetal heart rate and contractions suboptimal, and internal monitors may be utilized more often in this population. Obesity is a risk factor for obstetrical infectious complications, but it is unknown whether the use of internal monitors in this population is...

Background Anemia is one of the most commonly diagnosed comorbidities in pregnancy and is known to increase the risk of obstetrical complications. However, little is known about the effect of anemia on placental oxygen transfer and fetal oxygenation. Objective This study examined the relationship between maternal anemia and fetal oxygenation statu...

Introduction: Complication rates associated with peripherally inserted central catheters (PICCs) in the general population are variable, and rates specific to pregnant women are unclear. We conducted a systematic review and meta-analysis to estimate the rate of PICC-associated complications in pregnant women. Methods: We searched published literatu...

Objective The aim of this study is to determine the association between mild acidemia (umbilical artery [UA] pH: 7.11–7.19) and neonatal morbidity in neonates at term. Study Design This is a secondary analysis of a prospective cohort of women admitted for labor at ≥37 weeks of gestation within a single institution from 2010 to 2015. Universal umbil...

Because the obstetrical population seems to have a high proportion of asymptomatic patients who are carriers of severe acute respiratory syndrome coronavirus 2, universal testing has been proposed as a strategy to risk-stratify all obstetrical admissions and guide infection prevention protocols. Here, we describe a case of a critically ill obstetri...

Objective To estimate second stage duration and its effects on labor outcomes in obese versus nonobese nulliparous women. Study Design This was a secondary analysis of a cohort of nulliparous women who presented for labor at term and reached complete cervical dilation. Adjusted relative risks (aRR) were used to estimate the association between obes...

OBJECTIVES/SPECIFIC AIMS: Previous studies suggest that genetic variants in the oxytocin receptor (OXTR) may alter oxytocin dose requirement for labor induction and may increase risk for preterm labor and neurodevelopmental disorders. However, the mechanisms of actions of these variants remain unknown. The goal of this study was to functionally cha...

Objective To assess whether uterine tachysystole (UT) in labor causes an increase in cord blood lactate. Study Design Secondary analysis of a prospective cohort study of all consecutive singleton gestations ≥ 37 weeks admitted for labor to a single tertiary care institution with universal cord gas policy. Patients with UT in the last hour (“always”...

Objective: To compare the independent risk of neonatal morbidity between the offspring of obese and nonobese women without hypertension or diabetes. Methods: This is a secondary analysis of a prospective single-center cohort study of singleton deliveries at or beyond 37 weeks of gestation from 2010 to 2014. Women with diabetes (pregestational or...

Objective The objective of this study was to compare the rates of spontaneous labor onset and its progression in obese and nonobese women after 37 weeks. Study Design We performed a secondary analysis of a retrospective cohort of all women who were admitted for delivery at ≥ 37 weeks of gestation at a university-based tertiary care center between 2...