Dr. Chapa’s OBGYN Clinical Pearls

Today, we are talking about a true paradigm shift in prenatal genetics. For decades, we’ve relied on cell-free DNA for screening, but when it came to definitive confirmation of fetal aneuploidy, we’ve had to counsel our patients through the anxiety and physical risks of invasive procedures like amniocentesis and CVS. But what if the line between screening and confirmation just blurred? In this episode, we are diving into an avant-garde, first-of-its-kind maternal blood test that is now actively in clinical use and may prove to rival traditional invasive testing for fetal aneuploidy confirmation: the Unity CONFIRM test. To break down the cutting-edge science, the clinical validity, and exactly what this means for your daily practice, I am thrilled to welcome Jen Hoskovec, the Vice President of Medical Affairs for BillionToOne. You might have recently seen her insights featured alongside Dr. Haywood Brown in Contemporary OB/GYN, and today, she’s here with us. We’re going to discuss the availability of this test, the technology that makes it possible, and what the next concrete steps are for integrating this into modern obstetrical care. Grab your coffee. Let’s get into the science.
1. https://www.contemporaryobgyn.net/view/haywood-brown-md-jennifer-hoskovec-explain-new-non-invasive-confirmatory-test
2. Screening for Fetal Chromosomal Abnormalities PA; January 2026

Back in June 2024, we highlighted surprising data from JAMA Network Open regarding adolescent care in the ED. Because many adolescents use the ED as their primary care provider, it’s a good opportunity for them to have contraception addressed regardless of why they presented. But that’s not what was happening. That publication from two years ago showed significant gaps in addressing contraception in the ED to pregnancy vulnerable young women, mainly teens. We covered those results back then and said that that would be a wonderful QI project for any resident or medical students to work with their hospital ED to improve that. Well, now a similar publication, looking at a different target- STI empiric treatment among pregnant women in the ED, has been published with that same vibe. Yep, there are BIG discrepancies in what pregnant women are given- or in this case, NOT GIVEN, in the ED compared to their nonpregnant peers. This was published in mid-April 2026. Two big questions remain unanswered in this data. Listen in for details.

1. Gottlieb M, Moyer E, Slocum GW, et al. Sexually Transmitted Infection Treatment Rates Among Pregnant vs Nonpregnant Patients in Emergency Departments. JAMA Network Open. 2026.
2. Canter H, Reed J, Palmer C, et al. Contraception Use and Pregnancy Risk Among Adolescents in Pediatric Emergency Departments. JAMA Netw Open. 2024;7(6):e2418213. doi:10.1001/jamanetworkopen.2024.18213

It's a QUICKY: IMPROMPTU episode in clinic today..

Welcome back, everyone. Today we're diving into one of the most hotly debated topics in obstetrics- should we be treating preeclampsia without severe features with antihypertensive medications during expectant management? Now, if you've been following the literature- and our show, you know that the landmark CHAP trial changed the game for chronic hypertension in pregnancy. It showed us that targeting a blood pressure below 140 over 90 reduces serious maternal complications, without harming the baby. That was a big deal. But here's the thing, CHAP studied chronic hypertension. Then there was the CHIP trial- that also found that tight control of gestational hypertension and nonproteinuric chronic hypertension was also beneficial. These did not address preeclampsia without severe features, and yet, the ripple effects of that trial have sparked a global conversation about whether we should be extending those same treatment principles to women with preeclampsia who don't yet have severe features. And this is where it gets really interesting, because the guidelines don't agree. In the United States, ACOG and the Society for Maternal-Fetal Medicine still say: hold off on antihypertensives unless blood pressures hit the severe range at 160/110. But step outside the US, and you'll find the World Health Organization, the International Society for the Study of Hypertension in Pregnancy, FIGO, NICE, and Hypertension Canada all recommending treatment at 140 over 90, regardless of whether the diagnosis is chronic hypertension, gestational hypertension, or preeclampsia. So who's right? And more importantly what does this mean for the patient sitting in front of you right now, at 34 weeks, with a blood pressure of 150 over 95, some proteinuria, but no severe features? Today, we're going to break this down. We'll review the controversy, walk through the divergent guidelines, and most importantly talk about the real, practical implications that favor treating these patients during expectant management. Because when you're watching someone with preeclampsia, waiting for the right time to deliver, there's a strong argument that controlling their blood pressure isn't just reasonable…may be protective. So grab your coffee, settle in, and let's get into it.
1. Society for Maternal-Fetal Medicine Statement: Antihypertensive Therapy For mild chronic Hypertension in Pregnancy-The Chronic Hypertension And Pregnancy Trial. American Journal of Obstetrics and Gynecology. 2022. Society for Maternal-Fetal Medicine; Publications Committee.
2. Preeclampsia. The New England Journal of Medicine. 2022. Magee LA, Nicolaides KH, von Dadelszen P.

3. Antihypertensive Drug Therapy for Mild to Moderate Hypertension During Pregnancy.The Cochrane Database of Systematic Reviews. 2018. Abalos E, Duley L, Steyn DW, C.
4. Prevention and Treatment of Maternal Stroke in Pregnancy and Postpartum: A Scientific Statement From the American Heart Association. Stroke. 2026. Miller EC, Bello NA, Chen PR, et al.
5.Hypertension in Pregnancy: Diagnosis, Blood Pressure Goals, and Pharmacotherapy: A Scientific Statement From the American Heart Association. Hypertension. 2022. Garovic VD, Dechend R, Easterling T, et al.

The American College of Obstetricians and Gynecologists (ACOG) does not recommend routine ultrasound measurement of the lower uterine segment (LUS) thickness as part of the evaluation for trial of labor after cesarean delivery (TOLAC). ACOG Practice Bulletin No. 205 (2019) on Vaginal Birth After Cesarean Delivery does not include LUS measurement among its recommendations for TOLAC candidacy assessment. The guideline focuses on clinical factors such as type of prior uterine incision, number of prior cesarean deliveries, and other obstetric history to determine TOLAC candidacy, and emphasizes that most women with one previous low-transverse cesarean delivery should be counseled about and offered TOLAC. But what if you find a likely uterine window at the LUS? Does that mandate a repeat C-section? This topic comes from Serena, one of our podcast family members. Listen in for details.
1. Dr. Chapa’s Clinical Pearls, Dec 31., 2023: LUST FOR TOLAC; and follow up episode Jan 15, 2024
2. ACOG Practice Bulletin No. 205: Vaginal Birth After Cesarean Delivery. Committee on Practice Bulletins—Obstetrics Obstetrics and Gynecology. 2019;133(2):e110-e127. doi:10.1097/AOG.0000000000003078.
3. Rozenberg P, Sénat MV, Deruelle P, et al. Evaluation of the Usefulness of Ultrasound Measurement of the Lower Uterine Segment Before Delivery of Women With a Prior Cesarean Delivery: A Randomized Trial. American Journal of Obstetrics and Gynecology. 2022.
4. Swift BE, Shah PS, Farine D. Sonographic Lower Uterine Segment Thickness After Prior Cesarean Section to Predict Uterine Rupture: A Systematic Review and Meta-Analysis. Acta Obstetricia Et Gynecologica Scandinavica. 2019.
5. McLeish SF, Murchison AB, Smith DM, et al. Predicting Uterine Rupture Risk Using Lower Uterine Segment Measurement During Pregnancy With Cesarean History: How Reliable Is It? A Review. Obstetrical & Gynecological Survey. 2023.
6. Jastrow N, Demers S, Chaillet N, et al. Lower Uterine Segment Thickness to Prevent Uterine Rupture and Adverse Perinatal Outcomes: A Multicenter Prospective study.
7. American Journal of Obstetrics and Gynecology. 2016.
8. Guerby P, Bujold E, Chaillet N. Impact of Third-Trimester Measurement of Low Uterine Segment Thickness and Estimated Fetal Weight on Perinatal Morbidity in Women With Prior Cesarean Delivery. Journal of Obstetrics and Gynaecology Canada. JOGC. 2022.