Preimplantation and Stages of Fetus Development

Pregnancy is the most wonderful experience anyone could have, but what if you were unable to have successful pregnancies due to fertility issues or other complications? Pregnancy complications such as breech fetuses and unsuccessful implantation are a few of the many things that can go wrong. According to Gynecologist and Obstetrician Horace M Fletcher, “failed pregnancies are nature's way of taking care of what would perhaps otherwise have been an abnormal pregnancy; the egg is fertilized, but sometimes the fetus is abnormal and sometimes there is infection or low hormones”. Preimplantation can improve the success of implantation during embryonic development allowing them to revitalize and develop consistently without complications.

The preimplantation stage of a fertilized egg (conceptus) may be considered as a form of regenerative medicine since it is the composition of regenerative innovation, and a consistent IVF (in-Vitro fertilization) cycle that induces successful pregnancy. IVF is oocyte (cell in ovary that becomes ovum) fertilization performed in a Petri-dish. During IVF, embryos develop and are later transferred at the blastocyst stage into the uterus. The embryo is held in the laboratory between 2-6 days allowing it to develop into an organism composed of various cells upon which it will then be implanted in the uterus of the mother.

The blastocyst stage is the period in which the embryo undergoes a series of five or six mitotic cell divisions with an invariable volume known as a cleavage. Initially, at this stage, the embryo is ready to be implanted in the endometrium (inner lining of the uterus). However, the advice to transfer the embryo at blastocyst stage will be decided by your doctor and embryologist depending on your specific case for a higher probability of successful pregnancy. In addition, to ensure that the IVF procedure is effective, preimplantation testing for genetic abnormalities can be done. Preimplantation genetic diagnosis (PGD) is a procedure used prior to implantation to help identify genetic defects within embryo and serves to prevent certain genetic diseases or disorders from being passed on to the child.

On the contrary, the natural process of pregnancy without preimplantation begins with implantation and conception. Women release a group of eggs from the ovaries created in follicles (fluid-filled sacs) once a month. Ovulation occurs when the follicle expels an egg; ideally two weeks before a women’s upcoming menstrual cycle. Fertilization on the other hand, occurs two weeks after a woman’s last menstrual period when the sperm and egg fuse in one of the fallopian tubes. Upon fertilization if a Y-sperm cell fertilizes the egg the embryo will develop into a boy; whereas a X-sperm cell fertilizes the egg to develop into a girl.

The first trimester lasts for a period of up to 12 weeks in which the mother goes through a vast series of hormonal changes and the embryo begins to develop into a fetus. The levels of the hormone Human chorionic gonadotrophin (hCG) increase during pregnancy forcing the menstrual cycle to halt. Other hormonal changes mothers go through during the first trimester include but are not limited to: breast tenderness and frequent urination. The fetus is situated within the amniotic sac – a bag composed of membranes: amnion and chorion that secretes fluid that nourishes the baby as it undergoes development in the womb. The placenta (organ that transfers nutrients from mother to child and filters waste from the baby) is entirely formed at about 10 weeks. By the time you are 12 weeks pregnant your baby is approximately 60mm long; a primitive face forms in which your baby's forehead grows with the developing brain, the eyelids are still sealed shut and the ears are forming . In addition, your baby's central nervous system and heart begin reproducing making risks of birth defects crucial.

The second trimester lasts from 13 to 27 weeks. This timeframe involves growth of the fetal organs such as reproductive organs and maturation of the fetal skeleton. Red blood cells formulate as both the liver and pancreas go through emission. At four months, your baby’s teeth become denser and they can appear to be sucking their finger or even yawning. In addition, the baby’s bones strengthen within the second semester as their fetal skeleton matures due to the transfer of calcium from mother to child through the placenta. Five months in, your baby can make primarily slight movements in the womb as he /she becomes more active due to strengthened muscle development (babies can now make fists). A mother’s sensation of her baby’s movement in the womb is referred to as quickening.

As the third semester trickles down, both the bodies of the mother and child undergo a series of various changes as they prepare for birth. Your baby’s body continues to mature and reserve body fat while he or she may change position frequently while they respond to stimuli including sound, pain, and light. Braxton Hicks contractions (practice contractions) can start in the second trimester but can sometimes be mistaken for labour contractions.

However, these contractions only last about 25 seconds. Your baby's lungs mature throughout the third trimester and by 32 weeks your baby is much more likely to survive if born prematurely. During labor, the membranes of the amniotic sac rupture which conatively means that your water broke, and it is now time to prepare for delivery. This involves a sensation of wetness with a discontinuous spilling of watery liquid from your vagina that may be clear or pale yellow in color. Ideally, labour should occur after this process. However, in most cases there is an impediment such as a breeched fetus (baby born feet first). In other instances, some women experience premature rupture membranes (Preterm PROM) in which they go into early labor. Due to this complication they will have to endure a labor induced pregnancy as their doctor invigorates uterine compressions. Relatively, many things can go wrong during pregnancy.

A few pregnancy complications that can arise include ectopic pregnancy, miscarriage, and premature labor. An Ectopic pregnancy occurs when the fertilized egg attaches itself in a place other than inside the uterus. This pregnancy complication mostly occurs within the fallopian tubes and is thus referred to as a tubal pregnancy. Miscarriages can happen due to numerous reasons but mainly due to genetic abnormalities or changes in chromosomes due to mishaps when eggs split.

By conducting fertility treatments such as preimplantation, there will be an abatement of pregnancy complications and increment in implantation rates. Pre-implantation increases successful fetal development. Although a series of complications may arise during pregnancy and prevent its’ success, fertility treatments can be done to ensure that these issues are prevented. “Never confuse a single defeat with a final defeat”, F. Scott Fitzgerald.