Table 1.

Normal development of the Müllerian and its derivatives^*

Week of gestation post ovulation	Crown-rump (mm)	Heel-toe (mm) length	Carnegie Stage	Developmental event
3 wk	2.5 mm			Pronephric tubules form; pronephric (mesonephric) duct arises and grows caudad.
4 wk	3–5 mm		Stage 12	Pronephros degenerated, but mesonephric duct reaches cloaca.
5 wk	7 mm
6 wk	11 mm		Stage 17	Müllerian ducts appear as funnel-shaped opening of celomic epithelium.
7 wk	18 mm		Stage 22	Müllerian ducts migrate to about half distance to urogenital sinus.
	23 mm		Stage 23	Müllerian ducts extend caudally to near the urogenital sinus.
8 wk	30 mm		30 mm	Müllerian ducts begin midline fusion and make contact with urogenital sinus at the Müllerian tubercle.
	36 mm
9 wk	50 mm		56 mm	Müllerian ducts fuses (entire septum gone); Epithelium lining uterovaginal canal stratifies (1–2 cells layers thick).
10 wk	60 mm	2–5mm	60 mm
11 wk	71 mm	5–8mm	63 mm	Bilateral sinovaginal bulbs (evagination of UGS) appear.
	75 mm		75 mm	Vaginal plate first seen distinctly at 75 mm (complete at 140 mm; week 17).
12 w	93 mm	8–11mm
13 wk	105 mm	12–14mm	100 mm
14 wk	110–140 mm116 mm	15–17mm	110 to 140 mm	Marked growth of caudal vagina (between 110 & 140 mm).
			130 mm	Vaginal rudiment reaches level of vestibular glands; uterovaginal canal (15 mm total length) divisible into vagina (one-half), cervix (one-third), and corpus (one-sixth); boundaries ill defined.
				Endometrial stromal & myometrial layers of uterus become apparent.
				Solid epithelial anlage of anterior and posterior fornices appear
				Vagina begins to show slight estrogen (epithelial squamous differentiation)
15 wk	130–140 mm	18–21mm	135 mm	Cervix about 5 mm long
			139 mm	Uterine (Fallopian) tube begins active growth phase
			140 mm	Vaginal plate extends from vestibule to endocervical canal.
16 wk	142 mm	21–24mm		Uterine/cervical glands begin as outpouchings of simple columnar epithelium
			151 mm	Vaginal plate longest and begins to canalize.
			151 mm	Solid epithelial projections of anterior and posterior fornices demarcate cranial end of vagina.
17 wk	153–162 mm	24–27mm	160 mm	Palmate folds of cervix appear (forerunner adult cervix).
			162 mm	Mucoid development of cervix begins. Estrogen-induced thickening of vaginal epithelium.
18 wk	164 mm	27–30mm	170 mm	Fornices hollow.
19 wk	177 mm	31–33mm	180 mm	Cavitation of vaginal canal completed.
			185 mm	Uterine tube growth marked (~3 mm/week to week 34).
			190 mm	Cervix about 10 mm long.
21 wk	197 mm	37–40mm
22 wk	208 mm	40–43mm	200 mm	Vagina completely formed.
			210 mm	Differentiation of muscular layer of uterus complete.
			227 mm
24 wk	215–295	47–49mm		Uterine fundus well defined; uterus assumes adult form. Uterine body about 10 mm long.
25 wk	227
26 wk	240			Cervix about 20 mm long.
34 wk	305			Cervix about 25 mm long.
38 wk	362 mm			Birth.

^*Table compiled from (Koff, 1933; Mutter and Robboy, 2014; O’Rahilly, 1977; 1983; O’Rahilly and Muller, 1992; O’Rahilly and Muller, 2010)

NOTE: Week 1 includes = days 1–7, week 2 = days 7–14, etc.