Human health and medicine

Fetal alcohol syndrome

Fetal alcohol syndrome (FAS), also called syndrome alcoolique foetal, is the most severe fetal alcohol spectrum disorder: a teratogenic malformation syndrome from maternal drinking in pregnancy, marked by growth deficiency, three facial anomalies, and CNS impairment.

Fetal blood loss

Fetal blood loss (ICD-11 KA80, 胎児失血) is loss of blood from the fetal circulation during pregnancy, labour, or delivery, including fetomaternal hemorrhage, vasa praevia, ruptured cord, and co-twin hemorrhage, causing fetal anemia or death.

Fetal carbamazepine syndrome

Fetal carbamazepine syndrome, a drug embryofetopathy from prenatal carbamazepine exposure: facial dysmorphism, nail hypoplasia, spina bifida, cardiac and cleft anomalies, dose-dependent malformation risk.

Fetal cytomegalovirus syndrome

Fetal cytomegalovirus syndrome, also called congenital CMV (cCMV), results from transplacental CMV infection of the fetus; about 1 in 200 US newborns is infected, 1 in 5 develops sequelae, and sensorineural hearing loss is the leading disability.

Fetal Development

Fetal development: the week-by-week growth of a human from zygote to blastocyst, embryo (weeks 5–10), and fetus until birth at 37–42 weeks, plus clinical growth monitoring.

Fetal echocardiography

Fetal echocardiography is a detailed prenatal ultrasound of the fetal heart, the gold standard for diagnosing congenital heart disease before birth, typically performed at 18-22 weeks for high-risk pregnancies or abnormal screening.

Fetal electrocardiography

Fetal electrocardiography (fECG) records the fetal heart's electrical activity to assess cardiac rhythm and wellbeing, using noninvasive maternal abdominal electrodes or a fetal scalp electrode applied during labor.

Fetal Heart Rate

Fetal heart rate (FHR), also called fetal heart monitoring via cardiotocography or electronic fetal monitoring, is the fetus's heartbeat rate, normally 110–160 bpm, used to assess fetal well-being during labor.

Fetal heart rate monitoring

Fetal heart rate monitoring, called cardiotocography (CTG) or electronic fetal monitoring (EFM), records the fetal heart rate and uterine contractions during pregnancy and labor, and is the most common obstetric procedure in the United States.

Fetal hydantoin syndrome

Fetal hydantoin syndrome, also called phenytoin embryofetopathy, is a drug-related embryofetopathy from prenatal phenytoin exposure, causing craniofacial anomalies, nail and distal phalanx hypoplasia, growth retardation, and developmental delay in roughly 5 to 10 percent of exposed fetuses.

Fetal methylmercury syndrome

Fetal methylmercury syndrome, or congenital Minamata disease (水俣病), is prenatal brain poisoning caused when maternal seafood-borne methylmercury crosses the placenta, first certified in Japan in 1962.

Fetal Monitoring

Fetal monitoring: surveillance of fetal well-being in labor via intermittent auscultation (Pinard, Doppler) or continuous electronic fetal monitoring (cardiotocography, CTG). Halves neonatal seizures but raises cesarean rates; IA recommended for low-risk women.

Fetal pulse oximetry

Fetal pulse oximetry is a labor-monitoring technique that measures fetal arterial oxygen saturation through a sensor placed after the membranes rupture, as an adjunct to fetal heart rate monitoring.

Fetal surgery

Fetal surgery is the operative treatment of a fetus in the womb to correct congenital anomalies such as spina bifida, twin-to-twin transfusion syndrome, and diaphragmatic hernia.

Fetal Therapies

Fetal therapies are prenatal medical and surgical interventions, from transplacental drugs and ultrasound-guided procedures to fetoscopic and open surgery, for conditions such as twin-twin transfusion syndrome, congenital diaphragmatic hernia, and myelomeningocele, validated by trials including MOMS.

Fetal Tissue Transplantation

Fetal tissue transplantation: transfer of tissue from dead embryos or fetuses into patients, mainly fetal dopaminergic neurons for Parkinson's disease; two US RCTs (74 patients) showed no clear benefit; NIH banned elective-abortion fetal tissue research in 2026.

Fetal trimethadione syndrome

Fetal trimethadione syndrome is a pattern of birth defects from prenatal exposure to trimethadione, an antiepileptic drug used for absence seizures, first delineated in 1975.

Fetal valproate spectrum disorder

Fetal valproate spectrum disorder (FVSD), formerly fetal valproate syndrome, is a teratogenic condition from in utero sodium valproate exposure, causing facial dysmorphism, congenital malformations, and neurodevelopmental impairment including reduced IQ and autism.

Fetal viability

Fetal viability: the gestational point, generally 23-24 weeks in current U.S. practice, at which a fetus can survive outside the uterus; shaped by corticosteroid therapy, NICU care, and legal thresholds from Roe to Dobbs.

Fetal Weight

Fetal weight (estimated fetal weight, EFW) is the prenatal ultrasound estimate of a fetus's weight, computed from biometry (HC, AC, FL, BPD) via regression formulas, chiefly Hadlock; typical accuracy ±10%, worse at extremes and in twins.

Fetoscopes

Fetoscopes (also amnioscopes, embryoscopes) are endoscopes for viewing the embryo, fetus, and amniotic cavity. Used since 1967 for diagnosis, revived in the 1990s for fetoscopic laser surgery of twin-to-twin transfusion syndrome and fetal tracheal occlusion.

Fetoscopy

Fetoscopy is a minimally invasive prenatal procedure in which a fiber-optic endoscope inserted through the mother's abdomen views and treats the fetus, chiefly for twin-to-twin transfusion syndrome.

FETR-ALS trial

FETR-ALS (NCT03766321) was a four-center Italian randomized, sham-controlled proof-of-concept trial of fecal microbiota transplantation in 42 early-stage ALS patients; its Treg primary endpoint was not met, though slower ALSFRS-R decline was reported.

Fetus in fetu

Fetus in fetu (FIF), also called fetus-in-fetu, is an extremely rare parasitic monozygotic twin enclosed in its host twin, first described by Meckel around 1800, incidence 1 in 500,000 births, usually retroperitoneal, treated by complete excision.

FEV1/FVC ratio

FEV1/FVC ratio: spirometric index of forced expiratory volume in 1 second to forced vital capacity, also called the Tiffeneau index. A low ratio indicates airflow obstruction; GOLD uses <0.7, ATS/ERS/GLI use the LLN (z-score −1.645).

Fever

Fever, an elevated body temperature from a reset hypothalamic set point, mainly in infection; distinguished from hyperthermia. Antipyretics lower temperature but trials show no mortality or serious adverse event benefit.

Fever dream

Fever dreams are vivid, bizarre, often negative dreams occurring during fever (oral temperature 100.4°F/38°C or higher). Schredl's studies show they are more bizarre, emotionally intense, heat-themed, and lucid than normal dreams, likely because fever disrupts REM sleep.