Dating pregnancy with ultrasound Free sex chat like babble
Ameri-can College of Obstetricians and Gynecologists.
The timing of the "fertile window" in the menstrual cycle: day specific estimates from a prospective study BMJ 2000; 321: 1259-1262. Effects on the probability of conception, survival of the pregnancy, and sex of the baby.
Clinical management guidelines for obstetrician-gynecologists.
Number 4, May 1999 (replaces educational bulletin Number 147, October 1990).
However, ultrasound determination of the date of ovulation has the same imprecision as does the ultrasound estimate of the gestational age and, therefore, a precise date of conception cannot usually be determined as with in vitro fertilization.
Otherwise "..avoid missing a situation of early intrauterine growth restriction in one twin, most experts agree that the clinician may consider dating pregnancy using the larger fetus." [22,23]. Human Chorionic Gonadotropin Pregnancy Test Human chorionic gonadotropin first becomes detectable in the mother's blood and urine between 6 and 14 days after fertilization (3 to 4 weeks gestational age) [11-13]. The gestational age would, therefore, be at least 3 to 4 weeks at the time of a reliable h CG pregnancy test. Multifetal gestations: twin, triplet, and higher-order multifetal pregnancies. Page JM, The risk of stillbirth and infant death by each additional week of expectant management in twin pregnancies.