LMP, EDD & Duration of Pregnancy
Your first day of your last menstrual period is called your LMP. This is used to calculate your expected date of delivery [EDD] as well as how many weeks pregnant you are at any given time. You would actually have conceived about 14 days after your LMP and that is the date of conception although your pregnancy is always dated by convention from your LMP.
From your LMP a human pregnancy is of 40 week duration [38 weeks from date of conception]. A convenient way to calculate your EDD is to add 9 months and 7 days to your LMP. For example if your LMP is 1st Jan 04 then your EDD would be 8th Oct 04. Whenever you get a scan done your doctor will see if the age of the baby by the scan is corresponding to the age of the baby by your dates [LMP]. Your pregnancy is divided into 3 trimesters [thirds] of about 12 weeks each i.e:
• 1st trimester from conception to 12 weeks
• 2nd trimester from 12-24 weeks
• 3rd trimester from 24 weeks till the date of delivery.
The 1st Trimester
The 1st trimester is of 12 weeks duration and is when you first diagnose your pregnancy and have your first visit to your doctor [if you have not already had a pre conception consultation]. This is a difficult part of your pregnancy when you may experience some morning sickness, lethargy etc. You should really not worry about your diet at this stage and eat whatever pleases you. When you enter the 2nd trimester most of these symptom disappear and you will start to enjoy your pregnancy.
The 2nd Trimester
The 2nd trimester extends from the 12th week to the 24th week and is probably the most enjoyable period of your pregnancy. You will start to ‘show’ and feel the movements of your baby. Your doctor will put you on iron and calcium supplements and you will continue with your regular ante-natal check ups. A scan will be done at about 20 weeks to look for abnormalities in your baby, and a diabetes screening will be carried out at the same time. You will have a repeat Hb done at about 28 weeks and will get the first dose of the tetanus immunization at the same time.
You will have probably a number of complaints at this time, all of which should be reported to your doctor. Do not however expect treatment for each and every complaint as a large number of complaints are due to normal changes of pregnancy and do not as such require treatment. Some of the complaints that you may have are:
• Nausea & vomiting.
• Swelling of your feet.
• A sense of being bloated.
• Blood in your stools because of piles.
• Bleeding from the gums.
• Occasional abdominal pain.
• Dilatation of veins in your legs.
The 3rd Trimester
By this time you would start to feel a bit heavy. You will feel the babies’ movements very well and will have your second dose of tetanus immunization. You may be asked to repeat your scan and maybe have an NST test to see the health of your baby. Your ante-natal visits will be at more frequent intervals and your BP will be checked very carefully. You will have to look out for the following symptoms and if you notice any report to your doctor immediately:
• Abdominal pain.
• Vaginal bleeding.
• Gush of fluid-leaking.
• Decreased foetal movements-probably the most important of all.