Maternal Fetal Medicine

Contents

1. A subspecialty within the larger field
2. Two routes lead to a high risk label
3. Consultation, shared care or transfer
4. More visits, more scans, more people
5. Difficult deliveries draw on rare skills
6. The field’s research reaches the bedside slowly

Candace Cooley is a board certified obstetrician and gynecologist who has managed pregnancies of ordinary risk as well as high risk ones, and the second kind is where maternal fetal medicine begins. Consider a composite case. A woman of 40, with high blood pressure and a blood clot in her twenties, learns she is pregnant. Her obstetrician arranges for a subspecialist to see her early, adds growth scans to the usual schedule and notes which signs should prompt a call. Nothing dramatic has happened; the plan simply assumes that more can change in this pregnancy than in most, and assigns someone to watch for it.

A subspecialty within the larger field

Maternal fetal medicine is a formal subspecialty of obstetrics and gynecology, with its own training and its own examination. The specialty board for the field, ABOG, notes in a 2024 statement that its subspecialty certification has run for five decades and covers this discipline along with several others. The board adds that its examinations are built by subject experts through formal testing methods and kept current with practice in women’s health care, and that holding the credential signals maintained competence within a defined field rather than in teaching or administration.¹ A special report from the Society for Maternal Fetal Medicine describes the subspecialist as someone with advanced knowledge of the medical, surgical, obstetric, fetal and genetic complications of pregnancy and their effects on both mother and fetus.⁵

Two routes lead to a high risk label

An ACOG article written by a maternal fetal medicine specialist describes two ways a pregnancy becomes high risk. Sometimes the cause is the mother’s health: diabetes, high blood pressure, heart problems and age over 35 are among the most common. Other times the concern is found in the fetus, such as growth below normal or an abnormal amount of amniotic fluid. The author describes high risk as a spectrum running from pregnancies that are dangerous for the mother to those with only a somewhat greater chance of complications, and notes that more women now fall on it, as obesity rises and births come later in life.⁴ The Office on Women’s Health adds twins and other multiples, problems in an earlier pregnancy and conditions that arise during pregnancy, such as gestational diabetes and preeclampsia.⁸

Figure

Two routes into a high risk pregnancy

	The mother's health	Findings in the fetus
Typical examples	Diabetes, high blood pressure, heart problems, age over 35	Growth below normal, an abnormal amount of amniotic fluid
When it is known	Often before pregnancy begins	Usually on a routine ultrasound during pregnancy
Who else may join	The specialist who treated the condition before pregnancy	Pediatric specialists and the newborn intensive care team

Consultation, shared care or transfer

The Society’s report sets out three working arrangements. A subspecialist may consult and return the patient to her obstetric provider, may share care with that provider, or may take over the pregnancy entirely, and which arrangement fits depends on how serious the condition is and on local resources. The report also assigns the subspecialist roles in teaching colleagues and patients, in research and in leadership, and it stresses communication across the whole obstetric team. It encourages collaboration with obstetricians, family physicians and certified midwives, and counseling that reaches from before conception through the months after birth, so that complicated pregnancies receive care matched to their level of risk.⁵ The Office on Women’s Health makes the same division from the patient’s side: obstetricians care for women with health problems or higher risk, and women with the highest risk pregnancies may need a maternal fetal medicine specialist.⁸

Figure

Three ways a subspecialist shares the work

1. 01
   ConsultationThe subspecialist advises, and the referring obstetric provider continues the care.
2. 02
   Co managementThe subspecialist and the obstetric provider care for the patient together.
3. 03
   Transfer of careThe subspecialist takes over care of the complicated pregnancy.

More visits, more scans, more people

For the patient, the practical difference is volume, and the ACOG author is candid that the many appointments and tests can feel stressful and time consuming even as they serve to keep a close eye on mother and fetus. The ACOG article lists more frequent visits, extra ultrasounds to follow growth and, in the highest risk pregnancies, regular fetal monitoring. It notes that the specialist who managed a condition before pregnancy, such as a cardiologist or endocrinologist, should weigh in, and that the newborn intensive care team may be involved before birth. Delivery before 39 weeks is common, timed to come before a maternal condition can develop or worsen.⁴ Some conditions seen this way are common: a high risk obstetrician writing for ACOG describes gestational diabetes as affecting at least 1 in 20 pregnancies.³ How these extra checks layer onto the standard sequence is covered in the prenatal care schedule.

Difficult deliveries draw on rare skills

Some of the field’s skill is manual. In 2018 NPR followed a twin birth in which the second baby lay sideways in the uterus. An obstetrician who specializes in high risk deliveries, with more experience than most in such cases, reached in, found the baby’s legs and delivered him vaginally in a breech extraction, while colleagues stood ready to operate. The hospital was piloting a project to reduce cesarean births, and its rate among low risk first births fell from 31 to 27 percent in four months.²

The field’s research reaches the bedside slowly

Research is part of the subspecialist’s job, and preeclampsia shows how much remains open. In a 2026 report, NPR described an early trial of a new drug for the condition, whose only definitive treatment is still delivery; the drug appeared to lower blood pressure while improving blood flow to the placenta, though a maternal fetal medicine director not involved in the work called the study small.⁶ In 2025 STAT reported a study of more than 5,600 pregnancies that found a national risk guideline labeled 89 percent of patients at risk, while only a minority of them developed preeclampsia.⁷

Figure

Testing a national preeclampsia risk guideline

of patients classified as at risk

89%

of moderate risk patients who developed preeclampsia

10.5%

of high risk patients who developed it

23.5%

The evidence is strongest where it has overturned habit. The ACOG article notes that bed rest, once routine for high risk pregnancies, has not been shown to reduce any complication and raises the risk of blood clots, so ACOG no longer recommends it.⁴ The national screening panel behind the guideline STAT examined cites a rigorous research review showing that aspirin helps women at high risk prevent preeclampsia.⁷ What the subspecialty adds for any one woman is a matter for her and her own clinicians to weigh together.