A Partner's Guide to the First Trimester

Doctor with embracing couple

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If your partner is going to have a baby, congratulations! This can be an exciting and overwhelming time, and understanding just what's happening during pregnancy can help you prepare for baby's arrival. It can also help you support your significant other as she undergoes a variety of physical and emotional changes.

This pregnancy guide for partners will help you learn about the first 14 weeks of pregnancy, referred to as the first trimester. There is also information available for you when you reach the third trimester.

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The First Trimester

During the initial weeks of pregnancy, a woman's uterus grows from the size of a tangerine to that of a small melon.

Fetal Growth

The fetus grows from a fertilized cell that's invisible to the naked eye to a recognizable form with developing features. The face is formed with a properly developed mouth, nose, and eyes. You can see the outer ears. The internal organs are fully formed, although the lungs, liver, kidneys, and intestine need to continue to grow and mature.

By the 14th week, it is obvious what sex the infant is, and the external genital organs grow and mature.

Maternal Physical and Emotional Changes

At this stage, women may begin showing a small pooch, though the uterus is still somewhat small. Many women also suffer from morning sickness, which is something of a misnomer as it can happen all day long.

Women may begin to experience emotional changes due to hormone fluctuations. Know that this is normal, and lend your support to help her get through difficult periods. Good communication between you both is important. Having a close friend or family member to talk to about any concerns or worries you may have can be a great help.

Having Sex in the First Trimester

Having sex in the first 14 weeks of pregnancy should not present any health problems unless your partner has a history of miscarriage. You should avoid vigorous penetration, be gentle, and remember that her breasts may be tender or painful.

Prenatal Care

Pregnancy is a time for lots of doctor's visits, tests and waiting for results. One of your primary roles during this time is to provide support. Attending appointments will not only help you learn more about your baby's growth and development but also give your partner support.

Ultrasound scans let you see the baby's development. It is an amazing moment to see the tiny fetus for the first time. This and other tests can help determine your baby's health and if any abnormalities are present.

Other tests may include:

  • AFP: AFP is a screening test for neural tube defects. It is often done in combination with the measurement of other markers that together estimate the risk of down syndrome.
  • Amniocentesis: This test can help screen for genetic abnormalities and for fetal lung maturity.
  • Chorionic Villus Sampling (CVS): This test, which looks for genetic disorders, is done between 10 and 12 weeks of pregnancy.
  • Glucose Tolerance Testing: This simple blood test looks to see if the woman has developed a form of diabetes during pregnancy called gestational diabetes.
7 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Johns Hopkins Medicine. The first trimester.

  2. Kearin M, Pollard K, Garbett I. Accuracy of sonographic fetal gender determination: predictions made by sonographers during routine obstetric ultrasound scans. Australas J Ultrasound Med. 2014;17(3):125-130. doi:10.1002/j.2205-0140.2014.tb00028.x

  3. Jones C, Chan C, Farine D. Sex in pregnancyCMAJ. 2011;183(7):815–818. doi:10.1503/cmaj.091580

  4. MedlinePlus. Alpa-fetoproteint (AFP) test.

  5. Johns Hopkins Medicine. Amniocentesis.

  6. MedlinePlus. Chorionic villus sampling.

  7. MedlinePlus. Glucose screening tests during pregnancy.

By Jerry Kennard, PhD
Jerry Kennard, PhD, is a psychologist and associate fellow of the British Psychological Society.