Journal of Pregnancy and Child Health
Open Access

Gestation, also known as gravidity, is the time during which one or further seed develops inside a woman's womb. A multiple gestation involves further than one seed, similar as with halves. Gestation generally occurs by sexual intercourse, but can also do through supported reproductive technology procedures. A gestation may end in a live birth, a robotic confinement, an convinced revocation, or a birth. Parturition generally occurs around 40 weeks from the launch of the Last Menstrual Period (LMP). This is just over nine months (gravid age). Gestation is divided into three trimesters of roughly 3 months each. The first trimester includes generality, which is when the sperm fertilizes the egg [1].

The fertilized egg also travels down the Fallopian tube and attaches to the inside of the uterus, where it begins to form the embryo and placenta. During the first trimester, the possibility of confinement (natural death of embryo or fetus) is at its loftiest. Around the middle of the alternate trimester, movement of the fetus may be felt. At 28 weeks, further than 90 of babies can survive outside of the uterus if handed with high-quality medical care, though babies born at this time will probably witness serious health complications similar as heart and respiratory problems and long- term intellectual and experimental disabilities [2].

In humans, pregnancy can be defined clinically or biochemically. Clinically, pregnancy starts from the mother's last missed period. Biochemically, pregnancy starts when a woman's human Chorionic Gonadotropin (hCG) levels rise above 25 mIU/mL [3].

Human pregnancy can be divided into three trimesters, each approximately three months long: the first, second, and third trimester. The first trimester is from the last menstrual period through the 13th week, the second trimester is 14th–28/29th week, and the third trimester is 29/30th-42nd week.[5] Birth normally occurs at a gestational age of about 40 weeks, though it is common for births to occur from 37 to 42 weeks.[5] Labor occurring prior to 37 weeks gestation is considered preterm labor and can result from multiple factors, including previous preterm deliveries [4].

Timeline

The report of gestation is, unless else specified, generally given as gravid age, where the starting point is the morning of the woman's Last Menstrual Period (LMP), or the corresponding age of the gravidity as estimated by a more accurate system if available. Occasionally, timing may also use the fertilization age which is the age of the embryo [5].

Launch of gravid age

The American Congress of Obstetricians and Gynecologists recommend the following styles to calculate gravid age

• Directly calculating the days since the morning of the last menstrual period.
• Early obstetric ultrasound, comparing the size of an embryo or fetus to that of a reference group of gravidity of given gravid age (similar as calculated from last menstrual ages), and using the mean gravid age of other embryos or fetuses of the same size. However, it's still the bone from the early ultrasound that's used for the rest of the gestation. If the gravid age as calculated from an early ultrasound is antithetical to the one calculated directly from the last menstrual period [6].
• In case of in vitro fertilization, calculating days since oocyte reclamation orco-incubation and adding 14 days.

Trimesters

Gestation is divided into three trimesters; each lasting for roughly 3 months. The exact length of each trimester can vary between sources.

• The first trimester begins with the launch of gravid age as described over, that is, the morning of week 1, or 0 weeks 0 days of Gravid Age (GA). It ends at week 12 (11 weeks 6 days of GA) or end of week 14 (13 weeks 6 days of GA).
• The alternate trimester is defined as starting, between the morning of week 13 (12 weeks 0 days of GA) and morning of week 15 (14 weeks 0 days of GA). It ends at the end of week 27 (26 weeks 6 days of GA) or end of week 28 (27 weeks 6 days of GA) [7, 8].
• The third trimester is defined as starting, between the morning of week 28 (27 weeks 0 days of GA) or morning of week 29 (28 weeks 0 days of GA). It lasts until parturition.

Estimation of due date

Distribution of gravid age at parturition among singleton live births, given both when gravid age is estimated by first trimester ultrasound and directly by last menstrual period. Roughly 80 of births do between 37 and 41 weeks of gravid age.

Due date estimation principally follows two ways

• Determination of which time point is to be used as origin for gravid age, as described in the section over.
• Adding the estimated gravid age at parturition to the below time point. Parturition on average occurs at a gravid age of 280 days (40 weeks), which is thus frequently used as a standard estimation for individual gravidity. Still, indispensable durations as well as further personalized styles have also been suggested [9, 10].

I would like to thank my Professor for his support and encouragement.

The authors declare that they are no conflict of interest.

1. Bello FA, Akinyotu OO (2016) Predictors of successful induction of labour at a tertiary obstetric service in Southwest Nigeria. Trop J Obstet Gynaecol 33: 143-148.

Indexed at, Google Scholar, Crossref

2. Jaiswal S (2015) Indications, methods and outcome of induction of labor at Muhimbili national hospital, Dar es salaam, Tanzania: Muhimbili University.

Indexed at, Google Scholar, Crossref

3. Masan EJ (2013) Outcomes of induction of labor in women who delivered at Kenyatta national hospital: University of Nairobi.

Google Scholar, Crossref

4. Rayamajhi RT KC, Shrestha N, Padhye SM (2009) Induction and predictors for failed induction at KMCTH. Kathmandu Univ Med J 7: 21-25.

Google Scholar

5. Tarimo CS (2019) Prevalence and predictors of failure in labor induction among pregnant women delivered in Northern-Tanzania 2000-2015: A Registry-based Retrospective Cohort Study. Tanzan Med J 30: 13-36.

Indexed at, Google Scholar, Crossref

6. Lyndrup J, Legarth J, Weber T, Nickelsen C, Guldbæk E (1992) Predictive value of pelvic scores for induction of labor by local PGE2. Eur J Obstet Gynecol Reprod Biol 47: 17-23.

Indexed at, Google Scholar, Crossref

7. Khan NB, Ahmed I, Malik A, Sheikh L (2012) Factors associated with failed induction of labour in a secondary care hospital. J Pak Med Assoc 62: 6.

Indexed at, Google Scholar

8. Tripathy P, Pati T, Baby P, Mohapatra SK (2016) Prevalence and predictors of failed. Int J Pharm Sci Rev Res 39: 189-94.
9. Mbukani R, Kakoma J (2012) Is Nulliparity A Risk Factor For Poor Obstetrical And Neonatal Outcomes In Rwandan District Hospitals? A Prospective Observational Study at Muhima District Hospital. Rwanda Med J 69: 50-53.

Indexed at, Google Scholar, Crossref

10. Heffner LJ, Elkin E, Fretts RC (2003) Impact of labor induction, gestational age, and maternal age on cesarean delivery rates. Obstet Gynecol 102: 287-293.

Indexed at, Google Scholar, Crossref