A new parent with no time to practise
The first instruction in the Satipaṭṭhāna Sutta is short enough for a night feed: sit, hold the body upright, and breathe in and out with mindfulness. The canon describes practice as one's own territory, and the Metta Sutta takes a mother guarding her only child as its measure of a boundless heart. The acrobats' simile says that looking after yourself and looking after others are the same work, which is a fair description of a parent at three in the morning. Nothing here asks a sleep-deprived parent for longer sits. If you feel flat or numb most days, or cut off from the baby, tell your doctor or midwife soon; that is exactly what they are there for.
What the suttas say
It’s when a mendicant—gone to a wilderness, or to the root of a tree, or to an empty hut—sits down cross-legged, sets their body straight, and brings mindfulness to the present. Just mindful, they breathe in. Mindful, they breathe out. Breathing in heavily they know: ‘I’m breathing in heavily.’ Breathing out heavily they know: ‘I’m breathing out heavily.’
The first instruction in the Satipaṭṭhāna Sutta, in full and without elaboration.
MN 10:4.2–4.4 · Mindfulness Meditation
Idha, bhikkhave, bhikkhu araññagato vā rukkhamūlagato vā suññāgāragato vā nisīdati, pallaṅkaṁ ābhujitvā, ujuṁ kāyaṁ paṇidhāya, parimukhaṁ satiṁ upaṭṭhapetvā. So satova assasati, satova passasati. Dīghaṁ vā assasanto ‘dīghaṁ assasāmī’ti pajānāti, dīghaṁ vā passasanto ‘dīghaṁ passasāmī’ti pajānāti,
And how do you look after others by looking after yourself? By development, cultivation, and practice of meditation. And how do you look after yourself by looking after others? By acceptance, harmlessness, love, and sympathy.
The acrobats — the case that solitary practice is not selfish, and that care for others is itself practice.
Where this stops: For the worry that time given to one's own practice is taken from the people one cares for; not for a decision about having a child, and not a ruling on how to care for someone who is ill.
SN 47.19:3.1–3.5 · At Sedaka
Kathañca, bhikkhave, attānaṁ rakkhanto paraṁ rakkhati? Āsevanāya, bhāvanāya, bahulīkammena— evaṁ kho, bhikkhave, attānaṁ rakkhanto paraṁ rakkhati. Kathañca, bhikkhave, paraṁ rakkhanto attānaṁ rakkhati? Khantiyā, avihiṁsāya, mettacittatāya, anudayatāya—
If you roam inside your own territory, the domain of your fathers, Māra won’t find a vulnerability or get an opportunity. And what is a mendicant’s own territory, the domain of the fathers? It’s the four kinds of mindfulness meditation.
The quail and the hawk — practice as home ground, the place one is not easily caught.
SN 47.6:4.2–4.5 · A Hawk
Gocare, bhikkhave, carataṁ sake pettike visaye na lacchati māro otāraṁ, na lacchati māro ārammaṇaṁ. Ko ca, bhikkhave, bhikkhuno gocaro sako pettiko visayo? Yadidaṁ— cattāro satipaṭṭhānā.
Even as a mother would protect with her life her child, her only child, so too for all creatures unfold a boundless heart. With love for the whole world, unfold a boundless heart: above, below, all round, unconstricted, without enmity or foe. When standing, walking, sitting, or lying down while yet unweary, keep this ever in mind; for this, they say, is a divine meditation in this life.
The Metta Sutta's central image, in the canon's own words.
Where this stops: The verses are an ideal of the practitioner; the opening lines describing a skilled and honest person are a description, not a prerequisite for beginning. Never use it to quiet anger that has something to say, and never present it as a recitation that protects anyone. The mother guarding her only child is not for someone after a pregnancy loss.
Kp 9:7.1–9.4 · The Discourse on Love
Mātā yathā niyaṁ puttam Āyusā ekaputtamanurakkhe; Evampi sabbabhūtesu, Mānasaṁ bhāvaye aparimāṇaṁ. Mettañca sabbalokasmi, Mānasaṁ bhāvaye aparimāṇaṁ; Uddhaṁ adho ca tiriyañca, Asambādhaṁ averamasapattaṁ. Tiṭṭhaṁ caraṁ nisinno va, Sayāno yāvatāssa vitamiddho; Etaṁ satiṁ adhiṭṭheyya, Brahmametaṁ vihāramidhamāhu.
Parents served by the children in these five ways show sympathy to them in five ways. They keep them from doing bad. They support them in doing good. They train them in a profession. They connect them with a suitable partner. They transfer the inheritance in due time.
The parent's side of the eastern quarter — the canon's short job description for raising a child.
Where this stops: Arranging a marriage and handing over the inheritance belong to the ancient household; the first two duties are the portable ones. Never guidance on a child's safety, medical care or custody.
DN 31:28.3–28.4 · Advice to Sigālaka
Imehi kho, gahapatiputta, pañcahi ṭhānehi puttena puratthimā disā mātāpitaro paccupaṭṭhitā pañcahi ṭhānehi puttaṁ anukampanti. Pāpā nivārenti, kalyāṇe nivesenti, sippaṁ sikkhāpenti, patirūpena dārena saṁyojenti, samaye dāyajjaṁ niyyādenti.