Understanding Pregnancy: From Conception to Childbirth

Posted on Mar 1, 2025 in Biology

Pregnancy: From Conception to Childbirth

Pregnancy is the time that elapses from the fertilization of the ovum until birth. It takes about 38-42 weeks in a normal position. At 9 weeks of gestation, it is called an embryo (4cm and 5g). From September, it is called a fetus.

Placenta

The placenta is the organ through which metabolic exchanges take place between the fetus and the mother. It acts as a source of nutrition and respiration and releases hormones for gestation.

Changes in Pregnant Women

  • Menstruation absence: The sexual cycle is interrupted because hormone levels remain high.
  • Modification in the breast: Hypertrophy and increased mammary pressure occur. Areolas are pigmented, and nipples swell. Sometimes ducts secrete a clear liquid.
  • Changes in the skin: Striations appear in the abdomen and breasts. A dark vertical line may appear on the abdomen (linea alba), and spots may appear on the face.
  • Nausea with or without vomiting: Usually occurs in the early hours of the morning and disappears by the second or third month.
  • Pollakiuria: The cavity of the vagina decreases by pressure and is filled with a smaller amount of urine.
  • Enlargement of the uterus: The uterus undergoes hypertrophy, increased vascularization, and thickening of the endometrium, becoming part of the placenta. The cervix undergoes changes to prepare for delivery, increasing elasticity and forming a mucous plug that closes the uterus to the outside.
  • Increased secretion of saliva: Saliva will have a lower concentration of antibacterial substances, which favors caries.
  • Vagina and vulva: These become more elastic, and secretions from glands prevent infections.

Promoting and Improving Pregnancy Conditions

  • Oral hygiene: Visit the dentist and practice good oral hygiene.
  • Breast care: Perform proper breast care.
  • Sexual health: Certain positions are recommended during sexual relations.
  • Hygiene, clothing, and footwear: Wear baggy clothes and low, wide-heeled shoes.
  • Mental health: Women should continue their habitual occupations and resolve their doubts and fears.
  • Physical activity and rest: Remember that pregnancy is a physical condition. Great efforts and abrupt exercises should be avoided. Walking and exercises that strengthen muscles are recommended. Sleep at least 8 hours.
  • Birth preparation: Learn to relax and control breathing. Attend childbirth preparation classes.
  • Feeding: The body spends more energy, so a greater contribution is needed. You must eat *for* two, but not *like* two.

Additional Information

  • The membrane that surrounds the fetus (amnion) is a sac that contains a transparent and clear liquid, whose function is to protect the fetus by cushioning shocks (amniotic fluid).
  • Amniocentesis: Extraction by puncture of a sample of amniotic fluid and fecal cells for study. It is performed by the doctor with extreme asepsis, controlling a needle via ultrasound. It is not performed on all women.
  • Amnioscopy: An instrument is inserted through the vagina to the cervix to see the color of the amniotic fluid. The color indicates if there are complications. It is usually performed by a midwife.

Childbirth

Childbirth is the process by which the fetus comes out of the maternal body. Birth occurs when there are at least rhythmic, progressive, and painful uterine contractions every 10 minutes and 2 cm of cervical dilation. Oxytocin is the hormone that stimulates uterine contraction.

Uncomplicated Vaginal Delivery

This is the spontaneous expulsion through the genitals of a healthy, viable fetus and its annexes.

Stages of Labor

  1. Dilation: The pressure exerted by the bag of amniotic fluid and the fetus on the cervix causes it to dilate, becoming a wide hole that allows the fetus to exit the uterus. The dilation period lasts 12 hours in first-time mothers and 8 hours in multiparous mothers. At the end of this phase, the amniotic sac breaks.
  2. Expulsion: Begins when the cervix is fully dilated and ends with the fetus exiting. The fetus passes through what is known as the birth canal: the uterine cavity, cervix, and vagina. This stage is shortened to avoid tearing. It is extended through an incision in the perineum called an episiotomy.
  3. Birth of the Placenta: The detachment and expulsion of the placenta and membranes. The doctor or midwife checks the placenta.