Pregnancy OB Calculator

Pregnancy OB Calculator
OB Calculator

The OB Calculator is a computer program for Windows and DOS that will calculate a pregnant woman's due date and current gestational age. The calculations are based on any one of the following: last menstrual period, conception date, known weeks gestation, or weeks gestation based on an ultrasound examination. A custom table can be printed (two pages) showing how many weeks and days she has completed on each day of her pregnancy. Pregnancy milestones are also shown.
Every pregnant woman should know the gestational age of her pregnancy for the entire 40 weeks... in weeks and days, not in months. A sample table has been printed as a demo (see below). The OB Calculator program, which you can download, prints on paper a similar table based on your dates. Put your personalized print-out on the refrigerator door and track your progress!
If you find this program useful, please show the custom print-out to your OB caregiver. You may copy the program (OBCALC.EXE) onto a diskette and share it with your doctor or midwife. He or she can use the program to make print-outs for other pregnant women. The paper print-out is also very useful as a part of the OB caregiver's patient records.
Click here for download information on the OB Calculator.
The OB Calculator © 1995-2004 was developed by York Winston, M.D. It was written primarily for health care professionals, but can be used by anyone.
Send comments/suggestions by email to ywinston@cox.net.
Health care professionals can purchase the OB Calculator for $25. To arrange for purchase, send an email request. Or to pay by check, send $25 payable to York Winston, M.D. to 837 Royal Grove Ct, Chesapeake, VA 23320. A diskette with the latest version will be mailed to you.
In the example below, note that the months are listed across the top, and the days of the month are in the side margins. The due date is Oct 22. On July 5 she was 24 weeks plus 3 days, etc...
This print-out would normally fill two 8½ X 11 sheets of paper.

O B C A L C U L A T O R for ELLEN DEE Read month across, day down for (wks + days). Due Date: OCTOBER 22 Day JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC Day =============================================================================== 1 ---- 2+3 6+3 10+6 15+1 19+4 23+6 28+2 32+5 37+0 41+3 ---- 1 2 ---- 2+4 6+4 11+0 15+2 19+5 24+0 28+3 32+6 37+1 41+4 ---- 2 3 ---- 2+5 6+5 11+1 15+3 19+6 24+1 28+4 33+0 37+2 41+5 ---- 3 4 ---- 2+6 6+6 11+2 15+4 20+0 24+2 28+5 33+1 37+3 41+6 ---- 4 5 ---- 3+0 7+0 11+3 15+5 20+1 24+3 28+6 33+2 37+4 42+0 ---- 5 ------------------------------------------------------------------------------- 6 ---- 3+1 7+1 11+4 15+6 20+2 24+4 29+0 33+3 37+5 42+1 ---- 6 7 ---- 3+2 7+2 11+5 16+0 20+3 24+5 29+1 33+4 37+6 42+2 ---- 7 8 ---- 3+3 7+3 11+6 16+1 20+4 24+6 29+2 33+5 38+0 42+3 ---- 8 9 ---- 3+4 7+4 12+0 16+2 20+5 25+0 29+3 33+6 38+1 42+4 ---- 9 10 ---- 3+5 7+5 12+1 16+3 20+6 25+1 29+4 34+0 38+2 42+5 ---- 10 ------------------------------------------------------------------------------- 11 ---- 3+6 7+6 12+2 16+4 21+0 25+2 29+5 34+1 38+3 42+6 ---- 11 12 ---- 4+0 8+0 12+3 16+5 21+1 25+3 29+6 34+2 38+4 43+0 ---- 12 13 ---- 4+1 8+1 12+4 16+6 21+2 25+4 30+0 34+3 38+5 ---- ---- 13 14 ---- 4+2 8+2 12+5 17+0 21+3 25+5 30+1 34+4 38+6 ---- ---- 14 15 0+0 4+3 8+3 12+6 17+1 21+4 25+6 30+2 34+5 39+0 ---- ---- 15 ------------------------------------------------------------------------------- 16 0+1 4+4 8+4 13+0 17+2 21+5 26+0 30+3 34+6 39+1 ---- ---- 16 17 0+2 4+5 8+5 13+1 17+3 21+6 26+1 30+4 35+0 39+2 ---- ---- 17 18 0+3 4+6 8+6 13+2 17+4 22+0 26+2 30+5 35+1 39+3 ---- ---- 18 19 0+4 5+0 9+0 13+3 17+5 22+1 26+3 30+6 35+2 39+4 ---- ---- 19 20 0+5 5+1 9+1 13+4 17+6 22+2 26+4 31+0 35+3 39+5 ---- ---- 20 ------------------------------------------------------------------------------- 21 0+6 5+2 9+2 13+5 18+0 22+3 26+5 31+1 35+4 39+6 ---- ---- 21 22 1+0 5+3 9+3 13+6 18+1 22+4 26+6 31+2 35+5 40+0 ---- ---- 22 23 1+1 5+4 9+4 14+0 18+2 22+5 27+0 31+3 35+6 40+1 ---- ---- 23 24 1+2 5+5 9+5 14+1 18+3 22+6 27+1 31+4 36+0 40+2 ---- ---- 24 25 1+3 5+6 9+6 14+2 18+4 23+0 27+2 31+5 36+1 40+3 ---- ---- 25 ------------------------------------------------------------------------------- 26 1+4 6+0 10+0 14+3 18+5 23+1 27+3 31+6 36+2 40+4 ---- ---- 26 27 1+5 6+1 10+1 14+4 18+6 23+2 27+4 32+0 36+3 40+5 ---- ---- 27 28 1+6 6+2 10+2 14+5 19+0 23+3 27+5 32+1 36+4 40+6 ---- ---- 28 29 2+0 10+3 14+6 19+1 23+4 27+6 32+2 36+5 41+0 ---- ---- 29 30 2+1 10+4 15+0 19+2 23+5 28+0 32+3 36+6 41+1 ---- ---- 30 31 2+2 10+5 19+3 28+1 32+4 41+2 ---- 31 ------------------------------------------------------------------------------- Last menses = 0+0 Due Date: OCTOBER 22 Conception = 2+0 Due Date = 40+0 ELLEN DEE Based on LMP (28d) ANTICIPATED PREGNANCY MILESTONES: --------------------------------- Gestational Sac by U/S 7 Wks MAR 5 Heart Tones by Doppler 10-12 Wks MAR 26 to APR 9 Detailed Ultrasound Exam 18 Wks MAY 21 Fetal Movement Felt 18-21 Wks MAY 21 to JUN 11 Uterus at Umbilicus 20 Wks JUN 4 Onset of Labor 37-42 Wks OCT 1 to NOV 5 LAB SCREENING: -------------- CVS (if indicated) 10-12 Wks MAR 26 to APR 9 Amniocentesis (if indicated) 15-17 Wks APR 30 to MAY 14 Alpha Feto-protein (AFP) 15-20 Wks APR 30 to JUN 4 Diabetes Screen 24-28 Wks JUL 2 to JUL 30 Antibody Screen 28 Wks JUL 30 RhoGAM (if indicated) 28 Wks JUL 30 Hemoglobin/Hct 28 Wks JUL 30 Group B Strep Assessment 35-37 Wks SEP 17 to OCT 1 Copy of Record to Hospital 36 Wks SEP 24

Other Interesting Sites:

The Labor of Love pregnancy resource page

Ask Noah about pregnancy

Obstetrical Ultrasound

WellnessWeb home page

BabyTime Pregnancy Resource

Expert Advice About Kids

Return to top of page
Click here for download information on the OB Calculator.
Thanks for sharing this program with your OB caregiver!

You are visitor number since 10/8/98.