MRLS was initially characterized by four syndromes: (1) EFLs, (2) LFLs and the nonreproductive syndromes, (3) unilateral uveitis, (4) pericarditis, and later (5) "Actinobacillus" encephalitis. MRLS was observed in mares of all breeds and ages. Early and late fetal losses were observed within the first and last trimesters of pregnancy, respectively. For EFLs, clinical signs from the sick mares included pus-like discharge from the vulva and fetal membranes protruding from the vulva, as the fetuses were located in either the vagina or vulva. One to three days prior to the EFLs, several mares showed mild colic symptoms, abdominal straining, or low-grade fever. Within a week of abortion, inspections indicated moderate to severe inflammation within the uterine region. Performing ultrasounds revealed either dead fetuses or live fetuses with slow heart rates and lethargic movements. All the fetuses, both alive and dead, were surrounded by cloudy amniotic fluid.

Clinical signs for LFLs included explosive parturition, dystocia, foaling while standing, premature placenta separation, and foals either stillborn or born weak. Placentas were observed to carry a pale brown hue as opposed to their usual dark reddish-brown color. The umbilical cords were thick, dull, yellowish, and inflamed. The weak foals were often incapable of breathing on their own and required resuscitation. These foals were also observed to be dehydrated and hypothermic, with irregular heartbeat and respiration. The majority of these foals did not survive past four days.

One finding observed exclusively in MRLS was unilateral uveitis; initially, affected horses expressed inflammation around a single eye, along with fluid accumulation on the corneas, anterior and posterior chambers due to the inflammation. The fluid in the anterior chambers exhibited tan to yellow hues, and often was accompanied by hemorrhaging around the surface of the iris.

Mare reproductive loss syndrome (MRLS) is a syndrome consisting of equine abortions and three related nonreproductive syndromes which occur in horses of all breeds, sexes, and ages. MRLS was first observed in the U.S. state of Kentucky in a three-week period around May 5, 2001, when about 20% to 30% of Kentucky's pregnant mares suffered abortions. A primary infectious cause was rapidly ruled out, and the search began for a candidate toxin. No abortifacient toxins were identified.

In the spring of 2001, Kentucky had experienced an extraordinarily heavy infestation of eastern tent caterpillars (ETCs). An epidemiological study showed ETCs to be associated with MRLS. When ETCs returned to Kentucky in the spring of 2002, equine exposure to caterpillars was immediately shown to produce abortions. Research then focused on how the ETCs produced the abortions. Reviewing the speed with which ETCs produced late-term abortions in 2002 experiments, the nonspecific bacterial infections in the placenta/fetus were assigned a primary driving role. The question then became how exposure to the caterpillars produced these non-specific bacterial infections of the affected placenta/fetus and also the uveitis and pericarditis cases.

Reviewing the barbed nature of ETC hairs (setae), intestinal blood vessel penetration by barbed setal fragments was shown to introduce barbed setal fragments and associated bacterial contaminants into intestinal collecting blood vessels (septic penetrating setae). Distribution of these materials following cardiac output would deliver these materials to all tissues in the body (septic penetrating setal emboli). About 15% of cardiac output goes to the late-term fetus, at which point the septic barbed setal fragments are positioned to penetrate placental tissues which lack an immune response. Bacterial proliferation, therefore, proceeds unchecked and the late-term fetus is rapidly aborted.

Similar events occur with the early-term fetus, but as a much smaller target receiving an equivalently smaller fraction of cardiac output, the early-term fetus is less likely to be "hit" by a randomly distributing setal fragment. Since this MRLS pathogenesis model was first proposed in 2002, other caterpillar-related abortion syndromes have been recognized, most notably equine amnionitis and fetal loss in Australia, and more recently, a long-recognized relationship between pregnant camels eating caterpillars and abortions among the camel pastoralists in the western Sahara.

Advanced maternal age, in a broad sense, is the instance of a woman being of an older age at a stage of reproduction, although there are various definitions of specific age and stage of reproduction. The variability in definitions is in part explained by the effects of increasing age occurring as a continuum rather than as a threshold effect.

In Western, Northern, and Southern Europe, first-time mothers are on average 26 to 29 years old, up from 23 to 25 years at the start of the 1970s. In a number of European countries (Spain), the mean age of women at first childbirth has crossed the 30 year threshold.

This process is not restricted to Europe. Asia, Japan and the United States are all seeing average age at first birth on the rise, and increasingly the process is spreading to countries in the developing world like China, Turkey and Iran. In the U.S., the average age of first childbirth was 26 in 2013.

Advanced maternal age is associated with adverse reproductive effects such as increased risk of infertility, and that the children have chromosomal abnormalities. The corresponding paternal age effect is less pronounced.

In present generations it is more common to have children at an older age. Several factors may influence the decisions of parents when having their first baby. Such factors include educational, social and economic status.

There are various causes for recurrent miscarriage, and some can be treated. Some couples never have a cause identified, often after extensive investigations. About 50-75% of cases of Recurrent Miscarriage are unexplained.

Fifteen percent of women who have experienced three or more recurring miscarriages have some anatomical reason for the inability to complete the pregnancy. The structure of the uterus has an effect on the ability to carry a child to term. Anatomical differences are common and can be congenital.

Histologically, the pregnant sow suffers lesions in the myometrium due to the infiltration of monocytes.

The fetus presents: retarded growth, congestion of superficial vessels which may be associated with hemorrhage and dehydration which results in mummification of the fetus.

SMEDI (an acronym of stillbirth, mummification, embryonic death, and infertility) is a reproductive disease of swine caused by "Porcine parvovirus" ("PPV") and "Porcine enterovirus". The term SMEDI usually indicates "Porcine enterovirus", but it also can indicate "Porcine parvovirus", which is a more important cause of the syndrome. SMEDI also causes abortion, neonatal death, and decreased male fertility.

From an economic standpoint SMEDI is an important disease because of the loss of productivity from fetal death in affected herds. Initial infection of a herd causes the greatest effect, but losses slow over time. The disease is spread most commonly by ingestion of food and water contaminated with infected feces and occasionally through sexual contact and contact with aborted tissue. A vaccine is available (ATCvet code: ).

The condition gets its name because most, though not all, affected foals are born with a unique coat color dilution that lightens the tips of the coat hairs, or even the entire hair shaft. The color has variously been described as a silver sheen, a dull lavender, a pale, dull pinkish-gray, or pale chestnut. This dilution differs from gray foals because grays are born a dark color and lighten with age. It is also different from roan, because the hair is of a uniform shade, not of intermingled light and dark hairs.

Foals with LFS are unable to stand, and sometimes cannot even attain sternal recumbency (to roll from their side to lie upright, resting on the sternum, a precursor position to standing). They may lie with their necks arched back (Opisthotonos), make paddling motions with their legs, and often have seizures. extensor rigidity and seizure activity are also common signs. Apparent blindness may also be a clinical sign of the disorder, but is not seen in every case. Although they do have a sucking reflex, they cannot stand to nurse, and affected foals are usually euthanized within a few days of birth. There is no cure. In some cases, the mare may also have difficulty foaling, though foaling difficulties are not the cause of the condition. In some cases, LFS-affected foals may be larger than usual.

LFS is distinguishable from Neonatal Maladjustment Syndrome (NMS) or "Dummy Foal Syndrome".

A woman's risk of having a baby with chromosomal abnormalities increases with her age. Down syndrome is the most common chromosomal birth defect, and a woman's risk of having a baby with Down syndrome is:

- At age 20, 1 in 1,441

- At age 25, 1 in 1,383

- At age 30, 1 in 959

- At age 35, 1 in 338

- At age 40, 1 in 84

- At age 45, 1 in 32

- At age 50, 1 in 44

Lavender foal syndrome (LFS), also called coat color dilution lethal (CCDL), is an autosomal recessive genetic disease that affects newborn foals of certain Arabian horse bloodlines. Affected LFS foals have severe neurological abnormalities, cannot stand, and require euthanasia shortly after birth. The popular name originates due to a diluted color of the foals coat, that in some cases appears to have a purple or lavender hue. However, not all foals possess the lavender coat colour, colouring can range from silver to light chestnut to a pale pink. Carrier horses have no clinical signs and DNA testing can determine if a horse carries the gene.

Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects).

In humans, infertility is the inability to become pregnant or carry a pregnancy to full term. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all hetersexual couples have an unresolved problem with infertility. Many more couples, however, experience involuntary childlessness for at least one year: estimates range from 12% to 28%." 20-30% of infertility cases are due to male infertility, 20-35% are due to female infertility, and 25-40% are due to combined problems in both parts. In 10-20% of cases, no cause is found. The most common cause of female infertility is ovulatory problems which generally manifest themselves by sparse or absent menstrual periods. Male infertility is most commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity.

Women who are fertile experience a natural period of fertility before and during ovulation, and they are naturally infertile for the rest of the menstrual cycle. Fertility awareness methods are used to discern when these changes occur by tracking changes in cervical mucus or basal body temperature.

Symptoms may include tall stature, vertical skin folds that may cover the inner corners of the eyes (epicanthal folds), poor muscle tone, and a curve in the 5th finger towards the 4th. There may also be a small head (microcephaly). There are seldom any observable physical anomalies in triple X females, other than being taller than average.

Poor coordination may be present. Those affected appear to have higher rates of scoliosis.

Signs in mares appear ten to fourteen days after breeding to an infected or carrier stallion. A gray to creamy vulvar discharge mats the hair of the buttocks and tail, although in many cases, the discharge is absent and the infection is not apparent. Most mares recover spontaneously, although many become carriers. Infected mares are usually infertile during the acute illness. However, the infertility only lasts a few weeks, after which pregnancy is possible.

Stallions do not show signs of infection. The first indication of the carrier state is lack of pregnancy in the mares covered by the stallion.

Because the vast majority of triple X females are never diagnosed, it may be very difficult to make generalizations about the effects of this syndrome. The samples that were studied were small and may be nonrepresentative. Because of the lyonization, inactivation, and formation of Barr bodies in all female cells, only one X chromosome is active at any time. Thus, triple X syndrome most often has only mild effects or has no effects. The symptoms vary from person to person, with some women being more affected than others.

The pregnancy category of a medication is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. It does "not" include any risks conferred by pharmaceutical agents or their metabolites in breast milk.

Every drug has specific information listed in its product literature. The British National Formulary used to provide a table of drugs to be avoided or used with caution in pregnancy, and did so using a limited number of key phrases, but now Appendix 4 (which was the Pregnancy table) has been removed. Appendix 4 is now titled "Intravenous Additives". However, information that was previously available in the former Appendix 4 (pregnancy) and Appendix 5 (breast feeding) is now available in the individual drug monographs.

A bicornuate uterus or bicornate uterus (from the Latin "cornū", meaning "horn"), commonly referred to as a "heart-shaped" uterus, is a uterus composed of two "horns" separated by a septum. In humans, a bicornuate uterus is a type of uterine malformation, but in some other mammalian species, including rodents and pigs, it is normal.

Foals appear normal immediately after birth. JEB affects tissues including mucous membranes, so one of the first signs is blistering of the gingiva and tongue after the first attempt at nursing. Within the next few days, the foal develops lesions all over the body, especially over pressure points. The proteins affected by the gene mutations are also present in the hooves, causing hooves to slough.

Other symptoms that occur in JEB:

- Corneal lesions

- Dental dysplasia

- Depression

- Oral ulcers

- Suppressed appetite

- Incisors present at birth

Hypospadias presents as an abnormal location for the end of the urethra which is typically found on the distal end of the penis. It is generally diagnosed at birth from visual confirmation of the hallmark features. As well as an unusual location of the urethra, the prepuce (foreskin) is typically incomplete as well. The abnormal ‘hooded’ prepuce is what often draws attention to the condition but can occur separately to hypospadias.

It is possible to diagnose a bicornuate uterus using gynecologic ultrasonography, specifically sonohysterography, and MRI. However, as there is no indication to do such procedures on asymptomatic women, the presence of a bicornuate uterus may not be detected until pregnancy or delivery.

In a C-section (usually done due to malpresentation), the irregular shape of the uterus will be apparent.

Other less reliable diagnostic imaging methods include hysterosalpingography and hysteroscopy; these procedures are typically done during the course of an infertility investigation.

Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.

Cholinergic syndrome occurs in acute poisonings with OP pesticides and is directly related to levels of AChE activity. Symptoms include miosis, sweating, lacrimation, gastrointestinal symptoms, respiratory difficulties, shortness of breath, slowed heart rate, cyanosis, vomiting, diarrhea, trouble sleeping, as well as other symptoms. Along with these central effects can be seen and finally seizures, convulsions, coma, respiratory failure. If the person survives the first day of poisoning personality changes can occur, aggressive events, psychotic episodes, disturbances and deficits in memory and attention, as well as other delayed effects. When death occurs, it is most commonly due to respiratory failure from the combination of central and peripheral effects, paralysis of respiratory muscles and depression of the brain respiratory center. For people afflicted with cholinergic syndrome, atropine sulfate combined with an oxime is used to combat the effects of the acute OP poisoning. Diazepam is sometimes also administered in combination with the atropine and oximes.

The intermediate syndrome (IMS) appears in the interval between the end of the cholinergic crisis and the onset of OPIDP. Symptoms associated with IMS manifest within 24–96 hours after exposure. The exact etiology, incidence, and risk factors associated with IMS are not clearly understood, but IMS is recognized as a disorder of neuromuscular junctions. IMS occurs when a person has a prolonged and severe inhibition of AChE and has been linked to specific OP pesticides such as methylparathion, dichlorvos, and parathion. Patients present with increasing weakness of facial, neck flexor and respiratory muscles.

OPIDP occurs in a small percentage of cases, roughly two weeks after exposure, where temporary paralysis occurs. This loss of function and ataxia of peripheral nerves and spinal cord is the phenomenon of OPIDP. Once the symptoms begin with shooting pains in both legs, the symptoms continue to worsen for 3–6 months. In the most severe cases quadriplegia has been observed. Treatment only affects sensory nerves, not motor neurons which may permanently lose function. The aging and phosphorylation of more than 70% of functional NTE in peripheral nerves is one of the processes involved in OPIDP. Standard treatments for OP poisoning are ineffective for OPIDP.

COPIND occurs without cholinergic symptoms and is not dependent on AChE inhibition. COPIND appears with a delay and is long lasting. Symptoms associated with COPIND include cognitive deficit, mood change, autonomic dysfunction, peripheral neuropathy, and extrapyramidal symptoms. The underlying mechanisms of COPIND have not been determined, but it is hypothesized that withdrawal of OP pesticides after chronic exposure or acute exposure could be a factor.

Trimethylamine builds up in the bodies of patients with trimethylaminuria. The trimethylamine is released in the person's sweat, urine, reproductive fluids, and breath, giving off a strong fishy or body odor. Some people with trimethylaminuria have a strong odor all the time, but most have a moderate smell that varies in intensity over time. Individuals with this condition do not have any physical symptoms, and they typically appear healthy.

The condition seems to be more common in women than men, for unknown reasons. Scientists suspect that such female sex hormones as progesterone and estrogen aggravate the condition. According to several reports, the condition worsens around puberty. In women, symptoms may worsen just before and during menstrual periods, after taking oral contraceptives, and around menopause.

The odor seems to vary depending on many known factors, including diet, hormonal changes, stress level, amount of sweat, other odors in the space, and the observer's sense of smell.

Symptoms vary from case to case, and may correlate to how much of the chromosome is missing. Symptoms that are frequently observed with the condition include:

- Low birth weight

- Malformations of the head

- Eye abnormalities

- Defects of the hands and feet, polydactyly

- Reproductive abnormalities (males)

- Psychological and motor retardation

The symptoms of organophosphate poisoning include muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis. Other symptoms include hypertension, and hypoglycemia.

Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur.

The effects of organophosphate poisoning on muscarinic receptors are recalled using the mnemonic SLUDGEM (salivation, lacrimation, urination, defecation, gastrointestinal motility, emesis, miosis) An additional mnemonic is MUDDLES: miosis, urination, diarrhea, diaphoresis, lacrimation, excitation, and salivation.

The onset and severity of symptoms, whether acute or chronic, depends upon the specific chemical, the route of exposure (skin, lungs, or GI tract), the dose, and the individuals ability to degrade the compound, which the PON1 enzyme level will affect.

In Cryptorchidism a diagnosis is made from a physical examination which is performed when the baby is lacking one or both testes in the dependant portion of the scrotal sac. 70% of cryptorchid testes can be felt and are unable to be pulled into the scrotum or retreats quickly after being pulled into a higher position. In 30% of cases the testes cannot be felt indicating an intra-abdominal location. The risk factors for Cryptorchidism are:

- A family history of the condition

- Low birth weight

- Prematurity

"Asherman's Syndrome" is a condition characterized by adhesions and/or fibrosis of the endometrium particularly but can also affect the myometrium. It is often associated with dilation and curettage of the intrauterine cavity. A number of other terms have been used to describe the condition and related conditions including: intrauterine adhesions (IUA), uterine/cervical atresia, traumatic uterine atrophy, sclerotic endometrium, endometrial sclerosis, and intrauterine synechiae."