Skip to content

Health & Pregnancy

Twins Development 1st Trimester Highlights

Font Size
A
A
A

A lot has happened in the past three months. Your twins are only 3 or 4 inches long, but already can open and close their fists and mouths. Fingernails and toenails are just beginning to develop. Already, your tiny babies have: 

  • Brains, spinal cords, and flexible backbones.
  • Lungs, but not fully developed.
  • Hearts beating 120 to 160 beats per minute.
  • All major organs, but not fully developed.
  • Soft skeletons.
  • Eyes with eyelids that stay closed.
  • Noses, mouths, and chins.
  • Distinct fingers and toes and tiny fingernails.
  • Genitalia, but not fully developed.
  • Little teeth buds.

WebMD Medical Reference

Reviewed by Nivin Todd, MD on July 25, 2014

Pregnancy Week-By-Week Newsletter

Delivered right to your inbox, get pictures and facts on
what to expect each week of your pregnancy.

Today on WebMD

hand circling date on calendar
Track your most fertile days.
woman looking at ultrasound
Week-by-week pregnancy guide.
 
Pretty pregnant woman timing contaction pains
The signs to watch out for.
pregnant woman in hospital
Are there ways to do it naturally?
 
slideshow fetal development
Slideshow
pregnancy first trimester warning signs
Article
 
What Causes Bipolar
Video
Woman trying on dress in store
Slideshow
 
pregnant woman
Article
Close up on eyes of baby breastfeeding
Video
 
healthtool pregnancy calendar
Tool
eddleman prepare your body pregnancy
Video