The Playbook

27 Weeks Pregnant: End of the Second Trimester, Vaccines and You

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
Sizea cauliflower
Length / weightabout 14.4 in (36.6 cm), about 1.9 lb (875 g)

The baby sleeps and wakes on a regular cycle, opens and closes its eyes, and may suck its fingers. Brain tissue is developing quickly.

Your to-do list this week

  • Ask your own doctor whether your vaccines, including Tdap (whooping cough) and flu, are up to date. You'll be holding a newborn constantly.
  • Write down your three priorities for the third trimester and share them. Keep it to three.
  • Book the remaining appointments into your calendar; visits get more frequent from here.
  • Plan one last 'just us' weekend before 32 weeks.
A conversation to have this week

"What do you need most from me in the last trimester?" Then write down what she says. You'll need the reminder in week 36.

The baby this week

About two pounds, the baby now has regular cycles of sleep and wakefulness, opens and closes its eyes, and may suck its fingers (NHS). Brain tissue is developing quickly (Mayo Clinic).

How she may be feeling

The last week of the second trimester often comes with more fatigue, backache, leg cramps and swelling. Some people find the third trimester’s arrival exciting; others find it daunting. Both, often.

Shots and tests around now

Her provider may bring up:

  • Tdap. Recommended during each pregnancy, between 27 and 36 weeks, to pass whooping cough protection to the baby (ACOG).
  • Rh immune globulin. If she has Rh-negative blood, she’ll usually get a shot around 28 weeks to prevent her immune system from reacting to an Rh-positive baby (ACOG).
  • Glucose screening if it hasn’t happened yet.

And your vaccines

Newborns are especially vulnerable to some infections, like whooping cough, before they can be vaccinated themselves. Ask your own doctor whether you’re up to date on Tdap and the flu shot, and anything else they recommend for someone about to hold a newborn. Grandparents and regular caregivers might want to ask too.

Plan the third trimester

The last 13 weeks go fast and get physically harder for her. A short list beats a long one:

  1. Logistics: bags, car seat, route to the hospital, pre-registration.
  2. Work: leave approved, handover done by 36 weeks.
  3. Home: the safe sleep space ready, a few freezer meals, the basics bought.

Then protect one last weekend for just the two of you. You won’t regret it.

Frequently asked questions

Should dads get a whooping cough vaccine?

Whooping cough (pertussis) is most dangerous for newborns, who are too young to be vaccinated. The pregnant person's Tdap shot passes protective antibodies to the baby, and health organizations recommend that people who will be around the baby be up to date on their vaccines. Ask your doctor what's right for you.

Sources

  1. Routine Tests During Pregnancy, American College of Obstetricians and Gynecologists
  2. The Rh Factor: How It Can Affect Your Pregnancy, ACOG
  3. Fetal development: The 2nd trimester, Mayo Clinic
  4. Week 27: 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.