Pregnancy - Duration, Development, Trimesters | Britannica

pregnancy

Table of Contents

Introduction
The normal events of pregnancy
- Initiation of pregnancy
- Diagnosis of pregnancy
  - Symptoms and signs; biological tests
  - Conditions that may be mistaken for pregnancy
  - Duration of pregnancy
- Anatomic and physiologic changes of normal pregnancy
  - Changes in organs and tissues directly associated with childbearing
    - Ovaries
    - The uterus and the development of the placenta
    - Uterine tubes
    - Vagina
    - External genital structures
    - Other pelvic tissues
    - Breasts
  - Anatomic and physiologic changes in other organs and tissues
    - Cardiovascular and lymphatic systems
    - Respiratory tract
    - Gastrointestinal tract
    - Liver
    - Urinary tract
    - Blood
    - Endocrine system
    - Skin
  - Metabolic changes
    - The basal metabolic rate
    - Weight
    - Protein
    - Carbohydrates
    - Fat
    - Water
    - Minerals
- Prenatal care and testing
  - Ultrasound
  - Amniocentesis
  - Chorionic villi sampling
  - Alpha-fetoprotein screening
Abnormal changes in pregnancy
- Ectopic pregnancy
- Abortion
- Systemic diseases and pregnancy
  - Heart disease
  - Endocrine diseases
    - Diabetes
    - Thyroid disease
    - Pituitary disorders
    - Adrenal glands
  - Urinary tract diseases
  - Pulmonary disease
  - Gastrointestinal diseases
  - Nervous system disorders
- Diseases of pregnancy
  - Hypertensive disorders of pregnancy
  - Gestational diabetes
  - Diseases of the placenta
    - Placenta praevia
    - Abruptio placentae
    - Placental infarction
    - Placenta accreta
    - Placental cysts and benign tumours
    - Inflammation of the placenta
    - Placental anomalies
  - Anomalies of the umbilical cord
  - Abnormalities of the amniotic fluid
    - Hydramnios
    - Oligohydramnios
  - Trophoblastic disease
    - Hydatidiform mole
    - Choriocarcinoma

References & Edit History Related Topics

Images, Videos & Interactives

Learn how researchers use biobanks, such as the Improved Pregnancy Outcomes by Early Detection study, or IMPROvED to improve maternal and newborn outcomes

initiation of pregnancy; fertilization and implantation

How does a home pregnancy test work?

embryonic development

implanted human embryo

umbilical cord formation

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For Students

pregnancy summary

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There are, as a rule, 266 to 270 days between ovulation and childbirth, with extremes of 250 and 285 days. Physicians usually determine the date of the estimated time for delivery by adding seven days to the first day of the last menstrual period and counting forward nine calendar months; i.e., if the last period began on January 10, the date of delivery is October 17. Courts of law, in determining the legitimacy of a child, may accept much shorter or much longer periods of gestation as being within the periods of possible duration of a pregnancy. One court in ...(100 of 19882 words)

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