Pregnancy

The approximately 40-week physiological process in which a fertilized egg implants in the uterine lining and grows into a fetus, along with the resulting medical and social changes.

Pregnancy

Overview

Pregnancy (임신, 妊娠) is the physiological process in which a sperm and egg fertilize to form a zygote, which implants in the uterine lining and then grows into a fetus within the mother's body for about 38–40 weeks (around 280 days). Pregnancy is more than a simple biological event; it reshapes the mother's hormonal, circulatory, metabolic, and immune systems overall, and is broadly connected to the health of the mother and fetus, mode of delivery, and social and cultural perceptions. Medically, it is managed by dividing 40 weeks from the first day of the last menstrual period into three trimesters.

Key Content

1. Process of Establishing Pregnancy

When an ovulated egg meets sperm in the fallopian tube and is fertilized, it becomes a zygote; through repeated cell division it develops into a blastocyst and implants in the uterine lining. Implantation occurs about 6–10 days after fertilization, at which time human chorionic gonadotropin (hCG) is secreted and can be detected by a pregnancy test. Once implantation is complete, the placenta forms and is responsible for supplying nutrients and oxygen, excreting waste products, and producing hormones.

2. Changes by Trimester

  • First trimester (weeks 1–13): Morning sickness, fatigue, breast tenderness, and frequent urination are common. This is the period when the fetus's major organs form, making it most vulnerable to teratogenic factors (medications, radiation, infection).
  • Second trimester (weeks 14–27): Morning sickness decreases and fetal movement begins to be felt. Ultrasound screens for sex and major malformations, and gestational diabetes testing is performed.
  • Third trimester (weeks 28–40): Weight gain, edema, back pain, and contractions appear. Fetal position (head position) and placental status are checked, and delivery is prepared for.

3. Major Complications

Gestational diabetes, gestational hypertension and preeclampsia, anemia, preterm birth, ectopic pregnancy, miscarriage, and placental abruption are representative. Advanced maternal age (35 years or older), obesity, multiple gestation, and preexisting chronic diseases are factors that increase risk. Regular prenatal checkups (blood and urine tests, ultrasound, non-invasive prenatal testing, etc.) are key to early detection of complications.

4. Nutrition and Lifestyle Management

Folic acid (to prevent neural tube defects), iron, calcium, omega-3, and adequate water intake are recommended. Caffeine should be limited to 200 mg or less per day, and alcohol, smoking, and herbal ingredients should be avoided. Appropriate aerobic exercise, weight management, sufficient sleep, and stress relief are helpful. Vaccination (influenza, Tdap, etc.) and dental care are also important.

5. Childbirth and Postpartum

Modes of delivery include natural childbirth, cesarean section, and painless delivery, and are decided according to fetal status and maternal conditions. After childbirth, postpartum depression, pelvic floor dysfunction, and breastfeeding problems may occur, requiring postpartum checkups and emotional support.

Latest Trends

As of 2024–2025, several changes are appearing in pregnancy management. First, as non-invasive prenatal testing (NIPT) and cell-free DNA testing have become widespread, the accuracy of early screening for chromosomal abnormalities such as Down syndrome has increased. Second, ultrasound interpretation using artificial intelligence and technologies for predicting fetal heart rate and growth are being introduced into clinical practice. Third, evidence for the safety of vaccination during pregnancy (influenza, Tdap, COVID-19) has accumulated, and active recommendation is the trend. Fourth, in policies responding to low birth rates, discussions on expanding infertility support, cryopreserving embryos, and making prenatal testing covered by insurance are active. Fifth, the use of continuous glucose monitoring (CGM) and digital health apps is increasing in the management of gestational diabetes and obesity. Finally, in the field of maternal-fetal medicine, research on fetal surgery and gene therapy is underway, and maternal mental health management (screening for prenatal and postpartum depression) has become an essential item.

Related Topics

  • [[Obstetrics and Gynecology]]
  • [[Fetus]]
  • [[Childbirth]]
  • [[Infertility]]
  • [[Prenatal Testing]]
  • [[Breastfeeding]]
  • [[Postpartum Depression]]
  • [[Gestational Diabetes]]