The Playbook

15 Weeks Pregnant: Light Sensing, Body Changes and Kind Words

By the Guide to Fatherhood editorial team. Last reviewed . 2 min read.

Checked against guidance from organizations like the AAP, CDC, ACOG and NHS (linked below). This is general information, not medical advice. Read our medical disclaimer.

Trimester2
Sizean apple
Length / weightabout 4 in (10 cm), about 2.5 oz (70 g)

The baby's skeleton is hardening, and even with eyelids fused shut, the eyes can sense light. Legs are now longer than arms.

Your to-do list this week

  • Remind her (gently) to book a dental cleaning; pregnancy can make gums more prone to bleeding and inflammation, and routine dental care is safe.
  • If she's choosing second-trimester screening, the blood test window is usually 15 to 22 weeks.
  • Buy her something comfortable to wear, not a joke T-shirt. Ask the size; never guess.
  • Pick one parenting or birth book and read a chapter a week. Tell her one thing you learned.
A conversation to have this week

"How do you feel about your body changing, and what do you want me to say, or not say?" Some people love bump compliments; some want zero commentary. Ask, don't assume.

The baby this week

About the size of an apple, the baby is getting stronger. The skeleton is turning from cartilage to bone, the legs are now longer than the arms, and although the eyelids are still fused shut, the eyes can sense light (Mayo Clinic; NHS).

How she may be feeling

Hungrier, often less sick, and noticing her body changing faster. Increased blood flow can cause a stuffy nose and bleeding gums. Some people feel great; others feel off-balance and achy as the bump grows.

The gums thing is real

Pregnancy hormones can make gums swell and bleed more easily. ACOG says routine dental care is safe and important during pregnancy. If she’s overdue for a cleaning, now’s a good time.

Second-trimester screening

If you didn’t do first-trimester screening, or her provider recommends it, a second-trimester blood test (sometimes called a “quad screen”) is usually done between 15 and 22 weeks (ACOG). It screens for some chromosomal conditions and neural tube defects. As with all screening, results estimate risk; they don’t diagnose.

Talking about her body

This is a small topic that causes big damage when you get it wrong. Some guidance from dads who learned the hard way:

  • Ask, then follow her lead. Some people want daily bump photos. Some want to never hear the word “big” again.
  • Compliment specifics that aren’t about size. “You look happy.” “That color is great on you.”
  • Shut down other people’s comments. Relatives and coworkers feel strangely entitled to comment on pregnant bodies. Your job is to redirect: “She looks fantastic. Anyway, how’s your garden?”
  • Never joke about weight. Not even if she does.

Frequently asked questions

Is it safe to go to the dentist while pregnant?

Yes. ACOG says routine dental care, including cleanings, X-rays with shielding, and local anesthesia, is safe during pregnancy and encourages it, because pregnancy can increase gum problems.

Sources

  1. Fetal development: The 2nd trimester, Mayo Clinic
  2. Oral Health Care During Pregnancy and Through the Lifespan, American College of Obstetricians and Gynecologists
  3. Prenatal Genetic Screening Tests, ACOG
  4. Week 15: Your baby and your body, NHS

We link to the original source for every medical and safety claim. Guidance changes; if a source has been updated since our last review, the source wins. How we research.