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a period of 3 months.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(trī'mes-tĕr, trī-mes'ter),
A period of 3 months; one third of the length of a pregnancy.
[L. trimestris, of 3-months' duration]
Farlex Partner Medical Dictionary © Farlex 2012


(trī-mĕs′tər, trī′mĕs′-)
1. A period or term of three months.
2. One of three terms into which an academic year is divided in some universities and colleges.

tri·mes′tral (-trəl), tri·mes′tri·al (-trē-əl) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Obstetrics A period of 3 months, understood to be during pregnancy; the 1st trimester is 1-12 wks; the 2nd trimester is 13-26 wks; the 3rd trimester is 27 wks to delivery
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


A period of 3 months; one third of the length of a pregnancy.
[L. trimestris, of 3-months' duration]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


The first third or 13 weeks of pregnancy.
Mentioned in: Rubella
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


A period of 3 months.
[L. trimestris, of 3-months' duration]
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about trimester

Q. My daughter had lost her pregnancy in the second trimester. Something is going wrong with my daughter. She had lost her pregnancy in the second trimester. Something wrong was found in her ultrasound report. The situation was described as a molar pregnancy. After this miscarriage, still she is on regular examination. The very strange part is that they are still taking her hCG tests after her miscarriage. What sort of problem is this?

A. A molar pregnancy is a mass of tissue (hydatidiform mole) that forms an abnormal placenta inside the uterus. Even though it is not an embryo, a mole triggers symptoms of pregnancy. And the pregnancy test will result in positive value also. About 1 out of 1,000 women with early pregnancy symptoms has a molar pregnancy.

A molar pregnancy triggers the same first-trimester symptoms that a normal pregnancy does (a missed menstrual period, breast tenderness, fatigue, increased urination, morning sickness). It may be diagnosed during an early ultrasound test. In addition to normal pregnancy signs, a molar pregnancy usually causes additional symptoms, which can include:

Here are the most characteristic symptoms of a molar pregnancy :
Vaginal bleeding, a bigger size uterus that is abnormally large for the length of the pregnancy, severe nausea and vomiting, pelvic discomfort.

If you are diagnosed with a molar pregnancy, you will need immediate treatment to remove all molar growth fro

Q. I am in the final trimester and my whole stomach got really hard twice and hurt a lot. I am in the final trimester and from yesterday I am having extremely bad mental feeling and cramps and while at departmental store my whole stomach got really hard twice and hurt a lot....scared the hell out of me….it’s a heavy pain now, though I am relaxing now and still the pain seems to be arousing in a slow manner and I want to know what you all think?

A. Liam, since you're in your final trimester, be prepared to deliver your baby. I will suggest you to be more relax, and prepare yourself (physically, mentally, and emotionally) to deliver your baby at anytime.

Here I will share to you some real-labor symptoms :
- you will feel intensified contractions, it becomes stronger and more often
- the contraction will be more painful (that can feel like a cramp)
- you have bloody show (pinkish bloody streak from your down-there)
- you break the amniotic water

Okay, get prepared, and be ready to welcome your babyborn! Stay healthy always..

Q. My wife is pregnant and she is now in the first trimester. Her queasiness is disturbing her a lot. My wife is pregnant and she is now in the first trimester. Her queasiness is disturbing her a lot. She calls it as morning sickness. Almost all the day she feels nauseated whether she vomits or not. But every day she will throw once to have some relief for some time. I worry that this sickness can harm the baby. She does not want to meet the doctor as she says it’s normal with everyone who is pregnant. But I am worried can anyone give some advice?

A. my advice to you is the nausea and vomiting is a common thing that happens in first trimester. but be careful if the nausea and vomiting become more often and worse, by that time you must go to a doctor to find some help and therapy. it is called hyperemesis gravidarum.

so, make sure that what happened to your wife is in normal range, and good luck with her pregnancy! stay healthy always..

More discussions about trimester
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References in periodicals archive ?
Numerous studies have been conducted in the past to determine serum Hcy in both mild and severe form of preeclampsia but none compared serum Hcy levels in last two trimesters of normal pregnancies and preeclamptic primigravidas in Pakistan13.
The present study was devised to investigate alterations in hematological and cortisol levels in the three trimesters of pregnancy in the cows of Cholistani breed being reared under nomadic pastoralism.
Comparison of Frequency Domain Parameters in Trimesters of Pregnancy
Result: Out of 384 subjects, 188(48.95%) were in their first trimester and 196(51.04 %) females were in their second trimester.
With this ambiguity, the present study was undertaken to study the association of maternal haemoglobin in three trimesters with cord blood and newborn haemoglobin level.
"The teratologist review concluded no temporal association with CZP [certolizumab] exposure for the case of hydronephrosis, owing to evidence of anomalies on ultrasound prior to initiation of medication (during the third trimester); the possibility of an association could not be ruled out for the cases of anal fistula, accessory auricle, vesicoureteric reflux, talipes, and congenital heart disease," the researchers wrote.
[U.S.A], January 30 ( ANI ): According to a new study, it has been discovered that 64 percent of pregnant women suffer from insomnia in the third trimester of pregnancy, which is ten times higher than that for women suffering from insomnia prior to pregnancy.
Based on our findings, over 90% of Thai pregnant women who had no ultrasonographical evidence of ovarian or uterine tumor and no other possible causes of rising CA-125 showed a normal serum CA-125 value in the first and second trimesters. Only 9.02% of these pregnant women had a level of serum CA-125 more than 35 U/ml in the first trimester period.
Changes of Heart Rate and Blood Pressures at Three Trimesters. As shown in Table 1, HR increased significantly, and BPs (SBP and DBP) decreased significantly during normal pregnancy (all p < 0.01 with the comparisons between the first and second trimesters and between the first and third trimesters).
Data collected include maternal characteristics (age, parity), maternal prepregnancy weight, height, prepregnancy BMI, weight gain at the end of the 1st and 2nd trimesters of pregnancy, eating habits (such as eating between meals, taking or not of breakfast and consuming more fried foods) and the practice of physical activity (at least walking).
A median of the proportion of fetal-derived long DNA increased by 18% (P value <0.0001) in the third trimester when compared with the first trimester.
Moreover, several studies in the literature have investigated the effects of anemia in pregnancy by certain period, but in our study perinatal effects of anemia was investigated in all three trimesters of pregnancy.