RT Book, Section
A1 Bernstein, Helene B.
A1 VanBuren, George
A2 DeCherney, Alan H.
A2 Nathan, Lauren
A2 Laufer, Neri
A2 Roman, Ashley S.
SR Print(0)
ID 56964326
T1 Chapter 6. Normal Pregnancy and Prenatal Care
T2 CURRENT Diagnosis & Treatment: Obstetrics & Gynecology, 11e
YR 2013
FD 2013
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-163856-2
LK accessmedicine.mhmedical.com/content.aspx?aid=56964326
RD 2024/04/24
AB Pregnancy  (gestation)  is  the  physiologic  process  of  a  developing  fetus  within  the  maternal  body.  Several  terms  are  used  to  define  the  developmental  stage  of  human  conception  and  the  duration  of  pregnancy.  For  obstetric  purposes,  the  gestational  age  or  menstrual  age  is  the  time  elapsed  since  the  first  day  of  the  last  normal  menstrual  period  (LNMP),  which  actually  precedes  the  time  of  oocyte  fertilization.  The  gestational  age  is  expressed  in  completed  weeks.  The  start  of  the  gestation  (based  on  the  LNMP)  is  usually  2  weeks  before  ovulation,  assuming  a  28-day  regular  menstrual  cycle.  The  developmental  or  fetal  age  is  the  age  of  the  conception  calculated  from  the  time  of  implantation,  which  is  4  to  6  days  after  ovulation  is  completed.  The  menstrual  gestational  age  of  pregnancy  is  calculated  at  280  days  or  40  completed  weeks.  The  estimated  due  date  (EDD)  may  be  estimated  by  adding  7  days  to  the  first  day  of  the  last  menstrual  period  and  subtracting  3  months  plus  1  year  (Naegele's  rule).