Pregnancy weeks and fetal weights

Enter the first day of your last menstrual period.

Day: Month: Year:

Please note: these dates depend on the accuracy of the last menstrual period date you enter. Misremembering the date, delayed ovulation in cycles shorter or longer than 28 days, irregular periods or bleeding during pregnancy may mean that this date does not agree with your gestational age. It should therefore be confirmed against an ultrasound, preferably performed in the first trimester.

Weeks Dates Fetal weight, grams
End date of week 1:  
End date of week 2: Ovulation
End date of week 3: Implantation
End date of week 4: -
End date of week 5: -
End date of week 6: -
End date of week 7: <1
End date of week 8: 2
End date of week 9: 4
End date of week 10: 6
End date of week 11: 8
End date of week 12: 14
End date of week 13: 26
End date of week 14: 45
End date of week 15: 74
End date of week 16: 110
End date of week 17: 150
End date of week 18: 210
End date of week 19: 280
End date of week 20: 320
End date of week 21: 400
End date of week 22: 470
End date of week 23: 550
End date of week 24: 640
End date of week 25: 790
End date of week 26: 820 (550-1330)
End date of week 27: 960 (650-1500)
End date of week 28: 1050 (750-1680)
End date of week 29: 1300 (900-1900)
End date of week 30: 1400 (1000-2080)
End date of week 31: 1650 (1180-2350)
End date of week 32: 1780 (1300-2500)
End date of week 33: 2000 (1480-2750)
End date of week 34: 2200 (1680-2930)
End date of week 35: 2490 (1850-3200)
End date of week 36: 2700 (2080-3330)
End date of week 37: 2850 (2250-3500)
End date of week 38: 2950 (2500-3650)
End date of week 39: 3200 (2650-3800)
End date of week 40: 3350 (2770-3900)
End date of week 42: 3450 (2890-4050)

 

 The fetal weights in the table represent the 50th percentile, reflecting the average. The first number in brackets is the 10th percentile, the lower limit of normal, and the second is the 90th percentile, the upper limit of normal.

The nomograms are based on American and Canadian babies, the populations with the largest databases. For Turkish babies, particularly from week 26 onwards, values closer to the 10th percentile may need to be regarded as average.