When your baby won't stop crying

A 1-month-old baby communicates their feelings and needs by crying. Reasons for crying include hunger, a wet diaper, being too hot or cold, sleepiness, discomfort, boredom, or feeling unwell.
It's normal for babies at this age to cry for 1-3 hours a day, and in most cases, they are not sick.

As an anatomical and functional background, crying relies more on brainstem reflexes than the cerebral cortex, and for infants who do not yet possess language, crying is their only means of communication.
The digestive tract is still immature, the gastroesophageal junction is prone to reflux, and intestinal motility is unstable.
Bowel rhythms are also irregular due to the ongoing maturation of the enteric nervous system.

Methods to soothe a baby include holding them, skin-to-skin contact (Kangaroo Care), feeding (breastfeeding or bottle-feeding), changing their diaper, gently rocking, singing, or talking to them, swaddling them in a quiet environment, and gently massaging their belly or back.
When they won't stop crying, a safe option is to lay them down and allow the caregiver to take a break.

Leaking breasts

🌱Babies aged 1 to 3 months are in a period where their stomachs are immature and prone to spitting up. The lower esophageal sphincter (LES), which is the entrance to the stomach, is underdeveloped and has a weak anti-reflux function. Additionally, the stomach's shape is more vertical compared to adults, making it easier for contents to flow back due to gravity.
My stomach capacity is small, so it fills up quickly, and I vomit with only a little stimulation.
Additionally, delayed emptying from the stomach to the intestines and easier retention of contents can cause reflux. During breastfeeding, babies tend to swallow air, and if they don't burp, increased stomach pressure can promote reflux.

Given this anatomical and functional background, spitting up is a very common phenomenon in infancy.If your baby is nursing well and gaining weight, there's no need to worry.between 27 and 36 weeks of pregnancy.

🤢However,Green (bile-like) vomit, bloody vomit, projectile vomiting, poor weight gainIf any of these symptoms are present, you should suspect an organic disease and consult a doctor.

💩 Constipation

For a 1-month-old infant, if they have bowel movements every 4 to 5 days, but there is no vomiting or abdominal distension and their mood and feeding are good, it is considered a normal variation.
The number of bowel movements at this time varies greatly from child to child, and it is not uncommon for both breastfed and formula-fed infants to not have a bowel movement for several days.
Regarding stool color, green stools are frequently observed during infancy, and there's no need to worry if there are no other abnormal findings.

 🟢On the other hand, if symptoms of gastrointestinal obstruction—such as abdominal distension or vomiting—are present, an organic disease (such as Hirschsprung’s disease) should be suspected, and further evaluation and treatment are necessary.
🚨Alarm signs (e.g., fussiness, abdominal distension, vomiting, poor weight gain)If [condition] is recognized, interventions including enemas and drug therapy will be considered, but excluding organic diseases is important first.

🟢Most cases of constipation are functional, and unless there are any warning signs, the standard approach is to explain the situation to the parents and monitor the child’s progress.
If symptoms persist or worsen, re-evaluation is necessary. Drug therapy will be carefully considered only after organic disease has been ruled out.
The first choice is polyethylene glycol (PEG), which softens stool (approved for ages 2 and up in Japan).
Lactulose can also be safely used in newborns.
Magnesium oxide is widely used in Japan, but caution is advised due to the risk of hypermagnesemia in newborns.
Stimulant laxatives (like Lactulose) are not recommended for newborns.
Glycerin enemas are effective for temporarily removing impacted stool, but repeated use should be avoided. However, if a hard stool impaction (fecal impaction) has already formed, it may be difficult to improve with medication alone. After removing the stool using interventions such as enemas, lifestyle habits and drug therapy will be continued.

📚 References

Akaike T, Fukasawa T, Yanai T, et al. Patterns of Laxative Use in Japanese Children. Pediatr Int. 2025.

Zeevenhooven J, Browne PD, L'Hoir MP, et al. Infant Colic: Mechanisms and Management. Nat Rev Gastroenterol Hepatol. 2018.

Möller EL, de Vente W, Rodenburg R. Infant Crying and Calming Response. PLoS One. 2019.

Rosen R, Vandenplas Y, Singendonk M, et al. Pediatric Gastroesophageal Reflux Guidelines. JPGN. 2018.

Singendonk MM, Rommel N, Omari TI, et al. Upper GI Motility in Infancy. Nature Reviews Gastroenterology & Hepatology. 2014.

Solasaari T, et al. Bowel Function in Healthy Full-Term Infants. Eur J Pediatr. 2024.

Muhardi L, et al. Early-Life Gut Health Indicators. Nutrients. 2023.

Tabbers MM, DiLorenzo C, Berger MY, et al. ESPGHAN/NASPGHAN Guidelines on Constipation. JPGN. 2014.

Wells H, et al. Distal Intestinal Obstruction in Neonates. Pediatr Surg Int. 2024.

de Geus A, Gordon M, Sinopoulou V, et al. Pharmacological Therapies for Functional Constipation. Lancet Child Adolesc Health. 2025.

🧴 乳幼児のスキンケアと保湿剤使用（ガイドラインとエビデンス）