Antenatal Surveillance in Twin Pregnancies Using the Biophysical Profile

Fetal Growth and Antenatal Testing in Uncomplicated Multiple Gestations

Multiple gestations experience a slowing of fetal growth in the third trimester and have been described as having a higher risk of growth restriction. Whether this increased diagnosis of fetal growth restriction is physiological or pathologic is controversial. In an attempt to better identify those fetuses most at risk, twin-specific growth charts have been developed and tested. In addition, there are data to suggest that multiple gestations experience an increased risk of unexpected third-trimester stillbirth in apparently uncomplicated pregnancies. This chapter reviews the current data and recommendations for fetal growth assessment, antenatal surveillance, and delivery timing in uncomplicated multiple gestations.

Guideline No. 428: Management of Dichorionic Twin Pregnancies

OBJECTIVE

To review evidence-based recommendations for the management of dichorionic twin pregnancies.

TARGET POPULATION

Pregnant women with a dichorionic twin pregnancy.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline may improve the management of twin pregnancies and reduce neonatal and maternal morbidity and mortality.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary (e.g., twin, preterm birth). Results were restricted to systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date limits, but results were limited to English- or French-language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, radiologists, and other health care providers who care for women with twin pregnancies.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Indications for Outpatient Antenatal Fetal Surveillance: ACOG Committee Opinion, Number 828

ABSTRACT

The purpose of this Committee Opinion is to offer guidance about indications for and timing and frequency of antenatal fetal surveillance in the outpatient setting. Antenatal fetal surveillance is performed to reduce the risk of stillbirth. However, because the pathway that results in increased risk of stillbirth for a given condition may not be known and antenatal fetal surveillance has not been shown to improve perinatal outcomes for all conditions associated with stillbirth, it is challenging to create a prescriptive list of all indications for which antenatal fetal surveillance should be considered. This Committee Opinion provides guidance on and suggests surveillance for conditions for which stillbirth is reported to occur more frequently than 0.8 per 1,000 (the false-negative rate of a biophysical profile) and which are associated with a relative risk or odds ratio for stillbirth of more than 2.0 compared with pregnancies without the condition. Table 1 presents suggestions for the timing and frequency of testing for specific conditions. As with all testing and interventions, shared decision making between the pregnant individual and the clinician is critically important when considering or offering antenatal fetal surveillance for individuals with pregnancies at high risk for stillbirth or with multiple comorbidities that increase the risk of stillbirth. It is important to emphasize that the guidance offered in this Committee Opinion should be construed only as suggestions; this guidance should not be construed as mandates or as all encompassing. Ultimately, individualization about if and when to offer antenatal fetal surveillance is advised.

Multifetal Gestations: Twin, Triplet, and Higher-Order Multifetal Pregnancies: ACOG Practice Bulletin, Number 231

The incidence of multifetal gestations in the United States has increased dramatically over the past several decades. For example, the rate of twin births increased 76% between 1980 and 2009, from 18.9 to 33.3 per 1,000 births (1). However, after more than three decades of increases, the twin birth rate declined 4% during 2014-2018 to 32.6 twins per 1,000 total births in 2018 (2). The rate of triplet and higher-order multifetal gestations increased more than 400% during the 1980s and 1990s, peaking at 193.5 per 100,000 births in 1998, followed by a modest decrease to 153.4 per 100,000 births by 2009 (3). The triplet and higher-order multiple birth rate was 93.0 per 100,000 births for 2018, an 8% decline from 2017 (101.6) and a 52% decline from the 1998 peak (193.5) (4). The long-term changes in the incidence of multifetal gestations has been attributed to two main factors: 1) a shift toward an older maternal age at conception, when multifetal gestations are more likely to occur naturally, and 2) an increased use of assisted reproductive technology (ART), which is more likely to result in a multifetal gestation (5). A number of perinatal complications are increased with multiple gestations, including fetal anomalies, preeclampsia, and gestational diabetes. One of the most consequential complications encountered with multifetal gestations is preterm birth and the resultant infant morbidity and mortality. Although multiple interventions have been evaluated in the hope of prolonging these gestations and improving outcomes, none has had a substantial effect. The purpose of this document is to review the issues and complications associated with twin, triplet, and higher-order multifetal gestations and present an evidence-based approach to management.

Antenatal Testing for Women With Preexisting Medical Conditions Using Only the Ultrasonographic Portion of the Biophysical Profile

OBJECTIVE

To report the utility of the ultrasonographic biophysical profile, which includes all the components of a biophysical profile minus the nonstress test, in women with maternal indications for antepartum surveillance.

METHODS

We conducted a case series reviewing the records of all women at 32 weeks of gestation or greater with at least one indication for antenatal testing (per the American College of Obstetricians and Gynecologists) delivered by a single maternal-fetal medicine practice between 2006 and 2018. Indications included diabetes, hypertension, lupus, antiphospholipid syndrome, sickle cell disease, renal disease, heart disease, hyperthyroidism, isoimmunization, inherited thrombophilia, and prior intrauterine fetal demise. Weekly ultrasonographic biophysical profiles were initiated at 32 weeks of gestation. We calculated the test-positive rate, the percentage of women delivered for an abnormal ultrasonography biophysical profile, and the intrauterine fetal demise rate (false-negative rate).

RESULTS

Nine hundred eighty-five women underwent 3,981 ultrasonographic biophysical profiles (four per woman; range 1-11). Sixteen women had an abnormal ultrasonographic biophysical profile, for a test positive rate of 1.6% (95% CI 1.0-2.6%) per woman, or 0.4% (95% CI 0.3-0.7%) per ultrasonographic biophysical profile. Of the 16 women with abnormal ultrasonographic biophysical profiles, 13 were delivered with good outcomes and three women had normal follow-up testing and uncomplicated deliveries at a later date. There were three women with intrauterine fetal demise (false-negative rate of 0.3%, 95% CI 0.1-0.9%). One woman with intrauterine fetal demise had a factor V Leiden mutation, fetal ventriculomegaly, and fetal growth restriction. The second woman with intrauterine fetal demise had advanced maternal age, a factor V Leiden mutation, and fetal growth restriction. The third woman with intrauterine fetal demise had class B diabetes. All three intrauterine fetal demises were diagnosed antepartum with an interval from normal ultrasonographic biophysical profile to intrauterine fetal demise of 7, 7, and 6 days, respectively.

CONCLUSION

The use of ultrasonographic biophysical profile in a high-risk cohort is associated with a very low test-positive rate and a very low incidence of intrauterine fetal demise. In women with preexisting medical conditions that place them at higher risk for intrauterine fetal demise, ultrasonographic biophysical profile can be used for antenatal testing.