What to Expect During Pregnancy

 
 

What happens during pregnancy, week by week

Throughout pregnancy, a series of remarkable changes occur in the mother's body and the developing fetus. Here's a brief overview of pregnancy week by week:

Weeks 1-4: Conception typically occurs during week 2, with the fertilized egg implanting into the uterine lining around week 4.

Weeks 5-8: Organogenesis begins, and major organs and body systems of the embryo start to form. The heart begins beating, and limb buds develop.

Weeks 9-12: The embryo is now considered a fetus, and external features like fingers, toes, and facial features become more defined. The placenta forms to provide oxygen and nutrients to the fetus.

Weeks 13-16: The fetus grows rapidly, and its movements may be felt by the mother. Gender may be determined by ultrasound around week 16.

Weeks 17-20: Fetal movements become more noticeable, and the mother's abdomen starts to visibly expand as the uterus continues to grow.

Weeks 21-24: The fetus develops more mature organs, and its senses begin to develop. The lungs start producing surfactant, a substance necessary for breathing.

Weeks 25-28: The fetus continues to gain weight rapidly, and its brain undergoes significant development. The mother may experience Braxton Hicks contractions as the uterus prepares for labor.

Weeks 29-32: The fetus's bones harden, and its body fat increases. The fetus may adopt a head-down position in preparation for birth.

Weeks 33-36: The fetus's organs mature further, and it continues to gain weight. The mother may experience increased discomfort as the fetus takes up more space in the uterus.

Weeks 37-40: Full-term pregnancy. The fetus is considered fully developed and ready for birth. The mother may experience signs of impending labor, such as the baby "dropping" lower into the pelvis and the onset of regular contractions.

Of course, each pregnancy is unique, and variations in development and experiences can occur. Regular prenatal care with healthcare providers ensures the health and well-being of both mother and baby throughout the pregnancy journey.

The 101 on Prenatal Genetic Screening Tests

First-Trimester Screening:

  • This typically includes a combination of blood tests and ultrasound to assess the risk of chromosomal abnormalities such as Down syndrome (Trisomy 21) and Trisomy 18.

  • Blood tests measure levels of certain proteins and hormones, such as pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotropin (hCG).

  • Ultrasound measures the thickness of the fluid at the back of the fetus's neck (nuchal translucency).

    Cell-Free DNA Testing (cfDNA):

    • Also known as noninvasive prenatal testing (NIPT), this blood test analyzes fragments of fetal DNA circulating in the mother's bloodstream.

    • It can detect chromosomal abnormalities with high accuracy, including Down syndrome, Trisomy 18, and Trisomy 13, as well as certain sex chromosome abnormalities.

    • cfDNA testing is typically performed in the second trimester but can sometimes be done earlier.

    Second-Trimester Maternal Serum Screening (Quad Screen):

    • This blood test measures levels of certain proteins in the mother's blood, including alpha-fetoprotein (AFP), unconjugated estriol (uE3), hCG, and inhibin A.

    • It assesses the risk of neural tube defects (such as spina bifida) and chromosomal abnormalities.

    Carrier Screening:

    • Carrier screening tests are offered to parents to assess their risk of passing on genetic conditions to their offspring.

    • These tests identify whether individuals carry gene mutations associated with conditions such as cystic fibrosis, sickle cell disease, and Tay-Sachs disease.

    • Carrier screening can help couples make informed decisions about family planning and prenatal testing options.

    Diagnostic Testing (Amniocentesis or Chorionic Villus Sampling):

    • If prenatal screening tests indicate an increased risk of genetic conditions, diagnostic testing may be recommended to confirm the diagnosis.

    • Amniocentesis involves sampling amniotic fluid for genetic analysis, usually performed in the second trimester.

    • Chorionic villus sampling (CVS) involves sampling cells from the placenta for genetic testing, typically performed in the first trimester.

What is Morning Sickness and why does it happen?

Morning sickness, common in early pregnancy, is believed to result from hormonal changes, particularly elevated levels of human chorionic gonadotropin (hCG) and estrogen. These hormonal shifts can affect the gastrointestinal tract, leading to feelings of nausea and vomiting. Increased sensitivity to odors, slowed gastric emptying, stress, fatigue, and genetic/environmental factors may also contribute. While typically a normal part of pregnancy, severe or persistent symptoms may require medical attention.